Welcome to my Rammus Guide

WARNING: THE FOLLOWING GUIDE MAY SUCK BALLS

Intro

In League of Legends, Rammus seems to be a very unique champion. He can be played in tons of ways, although the main way is just as a tank. Here are some good things, and some bad things.

PROS

Very good tank if played well
Can take down towers and inhibitors pretty well
Hella annoying taunt that can and will give your team tons of kills
Strong mid-late game
You don't try to fight with an armadillo with ****ing spikes on his shell that has glowing eyes. You cannot deny the bad-***ery of this

CONS

A tank with moderately low HP???
Passive early game
Low mana efficiency
Very team dependent
Is almost always banned in ranked games

Summoner Spells

Cleanse

You are the tank, nuff said. Just kidding, but this is the thing that will keep you up and running when you are getting focused. Combined with Mercuy's Treads, you are 100% free of debuffs for 3 seconds. That, my friends, is pure win. This is required if you are going to tank well.

Ghost

I've heard rumors that Ghost actually makes you go through minions even during Powerball, but i've never had any issues with it, so, here it is. Ghost will allow you to catch up to people with Powerball with ease. Don't waste it though, it is very critical that you use it to catch up to enemies or something, not to get back to the tower a little faster...

Runes and Masteries

In all honesty, I don't really use runes very much, this playstyle can be further buffed using runes, but they're not actually needed. I just get magic resist glyphs and marks, and armor seals and quints. For masteries, I go 0/17/13. While most tank builds would go 0/21/9 or something, I take more points in Utility to get the improved mana regen, and since I don't really need Ardor or Improved Fortify, I just put the last point in movement speed. If you want different runes and masteries, go right on ahead. Almost no champion in the game is rune/mastery dependent. Also, since Rammus is almost always banned when it comes to ranked matches, they shouldn't make much of a difference.

Skills/Abilities

(Passive)Spiked Shell

Rammus gains additional damage as his shell becomes reinforced, converting 25% of his armor into damage.
A very nice passive, but as a tank, is irrelevant besides in early game. In late game, it is almost nonexistent.

(Q)Powerball

Rammus accelerates in a ball towards his enemies, dealing 100 / 150 / 200 / 250 / 300 (+100% of ability power) magic damage and causing 28 / 36 / 44 / 52 / 60% reduced movement speed to nearby enemies on impact.

Cooldown 12 seconds | Cost 80 / 90 / 100 / 110 / 120 mana | Range 300

This skill is maxed first, due to it's many capabilities. You can save a teammate by slowing his chaser, it deals great damage to help get a kill, it slows for a kill, and it makes you super fast, and this skill can be used to getting to different places fast, since you can use it from base to save mana, with a low cooldown. Don't randomly use it outside of base, becasue it is rather costy.

(W)Defensive Ball Curl

Rammus goes into a defensive formation for 6 seconds, increasing his armor and magic resistance by 50 / 75 / 100 / 125 / 150 and returning 26 / 32 / 38 / 44 / 50 (+25% of ability power) magic damage to attackers.

Cooldown 18 seconds | Cost 50 mana | Range 300

This ability is rather unique. As a tank, you will be maxing this a little earlier than most would expect. However, this ability is very dependent on who you are laning with. With Rammus's weak early game, he can be harassed very easily. Using this skill during an early game conflict can save your *** in bad situations. If you are laning with melee champions and they are harrassing and pushing more then they need to, put a point in taunt. You will learn why in the paragraph or two below. In general, this ability should be activated in any and every conflict, teamfight, turret tanking, getaway, chase, and gank, due to its great mana efficiency.

(E)Puncturing Taunt

Rammus taunts the unit into a reckless assault, reducing their armor by 10 / 15 / 20 / 25 / 30 and forcing them to attack Rammus for 1 / 1.5 / 2 / 2.5 / 3 second(s).

Cooldown 9 seconds | Cost 50 / 65 / 80 / 95 / 110 mana | Range 325

We max this ability last, but we do get it an early point. As I said in the paragraph above, maximization is really just dependent on who you are laning against. Against great harrassers, this takes the backseat. Against the passive or extremely squishy, don't be afraid to point a couple points in it. In late game, this can be deadly. One really fun trick you can pull off is when you are tower hugging, you can taunt your opponent and the turret will focus him once he attacks you. This is almost a guaranteed kill in early game, so don't hesitate to taunt an enemy next to an allied turret.

(R)Tremors

Rammus creates tremors beneath him, dealing 65 / 130 / 195 (+30% of ability power) magic damage per second to nearby units and structures. Lasts 8 seconds.

Cooldown 60 seconds | Cost 120 mana | Range 300

The awesome ultimate. This skill is, obviously, maxed out whenever possible. This can help score kills, and most importantly, own towers. With this, you can tank a tower with your team if you really want, and it should go down fast. It has a fairly short CD, so everytime you're 1v1ing, see if there might be a nearby team fight, and if not, then pop it, and you should have an easier time.

Items

Start off with a Doran's Shield for the armor, early game HP, and the health regen. If you are laning with a support, then get a Cloth Armor. For items afterwards, they are mostly situational tank items. If you are playing a tank, your items will always be dependent on which opponents you are facing. If you are facing a caster heavy team, get lots of MR. If you are facing a physical dps heavy team, then get lots of armor. If you are facing a good mix of both, then you should probably just go for whatever items best combat whatever champion is in your lane, or whichever one has the highest chance of causing you the most problems. Here are some examples of what items you should use against what kinds of threats that you are facing.

Anti-Caster

Mercury's Treads , Force of Nature, Banshee's Veil, Aegis of the Legion, Guardian Angel, Randuin's Omen or Shurelya's Battlesong

Anti-Physical DPS

Ninja Tabi or Mercury's Treads, Thornmail, Randuin's Omen, Aegis of the Legion, Guardian Angel, Sunfire Aegis

Why should I build these items?

Mercury's Treads:
With Cleanse, this item removes all debuffs, and prevents you from having ANY new debuffs for 3 seconds. This, with your summoner spells, is the true meaning, of GTFO NOW! MR is also good, and gives moderate movment speed. Buy against all CC Heavy Teams, and Caster Heavy Teams.
Force of Nature:
This is probably the death of all casters, as it gives INSANE MR, and the regeneration buff is good for all tanks. Not to mention, it gives movement speed for some reason... Rather pricy, but if you can spare, go for it.
Banshee's Veil:
Good mana, and health, with pretty good MR, but the fun comes with it's Passive. It blocks one negative spell every 30 seconds. While this isn't an amazing item, it will give you bragging rights when Karthus tries to ult, only to see his effort wasted as you walk off with 50 health chuckling to yourself.
Aegis of the Legion:
This item is more of a team item, and makes you a superb pusher. The Aura is great, and is definitely worth its cost.
Guardian Angel:
This is like a mini pocket- Zilean that has a 5 minute recharge. The cooldown sucks, but this can save your team's *** if you die prematurely.
Randuin's Omen:
How can you not get this item as a tank! The stats are pretty good with the health and armor, the passive is the bane of most physical DPS carries, and the active literally farms assists for you when you slow the entire squishy team and watch them all die to your carry/ies.
Shurelya's Battlesong:
This has the same idea as Randuin's Omen, but insteaad of slowing your enemies, it buffs you. If personally prefer Randuin's Omen because it can help if there is a turret, this can allow you to not take too much damage.
Ninja Tabi:
This item is very cheap, and with the dodge masteries, can help a lot in a 1v1, or a team fight. The armor fair, not too good though. Use it against physical DPS heavy teams.
Thornmail:
This item is pure rape against physical DPS heavy teams. 30% damage returned? That's killer! Combined with Defensive Ball Curl and Puncturing Taunt, you are the ultimate tank.
Sunfire Aegis:
This item has good armor and health, but the funny part is when you're in a team fight. Remember that every enemy around you takes 40 damage a second. That is pretty potent when you are being focused. While this is not actually a plus, it looks pretty funny when you Powerball towards others, and it looks like you're on fire. just saying.

Ordering

This is probably the most game dependent variable possible. This is pretty much how it comes down. After you start with your Doran's Shield or Cloth Armor, then get your boots as your second item. Even if you are fed, boots are first priority. Why? Because boots will give you the movement speed you need to be useful in team fights, and the speed to GET to team fights. If you're casually farming bot while your team is getting their ***es whupped in mid, and you can't get to mid, then you were completely useless, and you did not accomplish your goal as a tank. You have to be with your team. Like I said in the Cons, Rammus is very team dependent. What I didn't also mention (if you didn't already know) was that your team is dependent on you. A useless Rammus, is almost as bad as a feeder. Think about this, if your team decides that for their setup, that you are the only tank, and you're not there to help out, then your team has a pretty dang large chance of getting aced, and probably surrendering at 25 mins.

If you come back after a first blood or something like that, or anytime far from a team fight, then you can skip boots, and build conventional tank items, or an Elixir of Fortitude. If you need to decide which boots to get, look at who is the biggest threat. If it's Ryze, who rune prisons you all the time, then you might wanna get your Mercury's Treads. If you're problem is Master Yi, who's Physical DPS is getting really annoying, get Ninja Tabi for the excellent dodge stats. If you're playing against total noobs that don't know what Pantheon's ult is and try to stand in the middle of it, then get Mobility Boots.

If you still have extra money that you cant spend on any core items, then just get some Health Potion. After the boots, do the same check, but this time more on damage output. If the Karthus who somehow one hits you with his ult is starting to piss you off, then get some magic resist. I suggest either an early Force of Nature, or if it's really being a pain, get the Banshee's Veil. You probably won't be able to finish it, so start with a Negatron Cloak. If the enemy Tryndamere is owning with his crits, then get some armor. I suggest a Thornmail if you can (Passive is amazing against most carries) or maybe the Aegis of the Legion. Remember, part of deciding which item to buy is also using intuition to see what your allies are having a hard time with, because their problems, are your problems, and you will be tanking so you have to know who is a threat and who isn't. Remember, if you get an item that is supposed to build another core item, and another threat arises, do no hesitate to buy another part of a different core item to counter that threat.
For the rest of the game, just try to continue building your items, in the same order as before. What threat is the most potent, or most annoying? Build against it, and your team will thank the hell out of you.

GAMEPLAY

Early Game

For the early game, this is the worst time for you. And sadly, it will completely decide the rest of the game for you. First thing is first, get a lane partner (and a life you overweight bastard, jk, or not...). For Rammus, you do not want to lane with someone who has weak DPS. Support champions are acceptable, but you want a stable DPS champion, maybe a Xin Zhao or a Master Yi. In general, you want to lane with someone who NEEDS champion kills, since you don't need them. If you get a support like Soraka, then you can be more agressive, but you'll also need to put a couple extra points into taunt so you can defend him/her. If you get the carry, then just stay passive, occasionally picking up the last hit that was missed, and just kinda chill, collecting XP. If you get the support champ, then pick up the last hits, if you can, taunt, and harass, and your support will heal you when you are low. But for gods sake don't tower dive like a mofo. You will only die a quick and terrible death. That's for late game :). Just rinse and repeat until you see a ganking opportunity. Once you do, your Mid Game has begun.

Middle Game

Once you find a ganking opportunity, go back, and run back to base, grab any items you might need, and go gank (don't forget to tell your team mates). If you can, let any other carry helping to get the kill get the last hit. Your carries need your gold more than you do, so just farm your items up. Go back to your lane and farm, or gank again. Rinse and repeat, and just farm up your items. Remember, if your allowing your carry to get the kill, and the prey is getting away, just take the kill. If a team fight breaks out, then there's something you need to think about. Who's fed? Who's "MIA"? Who is the most important carry? As you keep this in mind, try to target the fed, taunt the stragglers, turn on your ult, keep up you shield, and powerball the **** out of any squishies. This is going to be your tank sequence for most of your team fights. During team fights, even though you are the tank, you are not the initiator. Have a tough champion initiate to draw attention first, then Powerball in from behind and try to take on all of the aggro. Taunt the enemy carry/fed champ, or a straggler that will probably die, and begin the rampage. If you have Defensive Ball Curl on, then you could initiate, but just for the shock value of a tank that you can barely damage attacking from behind, and the team carry charging your face, your opponents (assuming they're not fed) will be fairly intimidated. With Soaring Slam on, your opponents would be wise to stay clear from you. Just remember that you are not even close to invincible during mid game. You are relatively squishy mid game, so beware of champions with true damage like Olaf and Cho'Gath who will rip you to shreds if you are squishy. Remember that you can push lanes if nothing is really going on.

Late Game

Around this time, you should be getting your final core items, and if the match is still split, just team up in one mid, and push like crazy. If you have lots of CC, then arrange random group ganks to stir widespread fear whenever the entire team is mia. Make your opponents feel that they have to hug the towers. If you have good armor, then you are a superb tower diver. NOW you can taunt enemies near the tower, seeing as to how you can probably tank the tower for your team efficiently with your Defensive Ball Curl. One of the main things about playing LoL that i find that is missed by many players, is that there is more to LoL, then having a good build. One thing that Rammus can do extremely well, is to scare the living **** out of people after the entire team has disappeared. The jungle is your friend, and you should have people on your team with oracles to see wards and traps. If the enemy team doesn't have wards in the jungle, then you can essentially gank and push however you please, and your enemies will be forced to place wards, only to have them destroyed. Once good tactic that you can use is if you stumble upon, for example, a Noxious Trap, then move forward until the debuff is gone, and turn around and gank someone else, and take unexpected paths to do so. This works especially well on a ventrilo server, or arranged teams. If you can scare your opponent into being afraid of the jungle, then you have yourself an extremely potent advantage, and you should have no trouble trumping them by ganking, pushing, and eventually, once all of your team's builds are complete, or earlier, kill baron, and make a super push (Rammus can just tank the towers) to win.

Tips & Tricks

Always have good map awareness. Twitch mia? Call it and be cautious. Fast Junglers? Don't push the tower too hard. Always make sure that you don't feed, and keep you're lane mate alive.

Farming with Powerball should only be used in the situations where you have some clear gold advantages that outweigh the mana. For example, don't use Powerball to farm up two minions, use it when there are four or more minions to kill. The other case is when you're going to go back to base anyways and you have some mana, so just use it and leave.

Use the bush! For weak early game melee champions, the bush is an extremely potent area for disruption of opposing farmers. Since many spellcasters have their nuke as targeters. The bush is a good place to use to evade spells. Start in bush. Quickly run out and harrass, then go back in. Rinse and repeat. If both laning partners are doing this, then you have yourself an annoying duo that has good chances of early kills if you're playing against someone like

Katarina or Fiddlesticks

Acknowledgements

I would like to thank Jebus McAzn, and EldRefr for suggesting that I give more optimization for the points in taunt, or Defensive Ball Curl
Thanks to everybody else for the positive feedback! Trolls, thanks for holding in the urge to spam vote!

Conclusion

This is my first build, so if the trolls get their hands on it, I probably won't be too surprised. I am open to constructive criticism, so I actually really need some suggestions for the Masteries and runes, so... vote if you like it. If you don't like it, vote down then. Whatever. Whatever your opinion, leave a comment. I might just make a change in the build. If you need any clarification about anything, I'll see that i have the time to answer your questions. Thanks.