Hey guys! This will be the second guide I made on Mobafire :3 This build for rammus is just about getting as much armor as possible to take advantage of your passive, Spiked Shell and Defensive Ball Curl (:

Greater Mark of Attack Speed You will have a decent amount of AD due to your passive and so I like to grab AS Marks to allow me to dish it out. Helps with pushing towers too (:
Alternatives are:
Greater Mark of Magic Penetration as a bulk of your damage output is Magical ( Thornmail, Powerball, Defensive Ball Curl, Soaring Slam and Sunfire Aegis) though I personally find 8.5 MPen not really worth it.
Greater Mark of Armor For a little extra starting armor (:
or Greater Mark of Magic Resist For more MR

Greater Seal of Armor Yay!!! More armor :3
Alternatives are:
Greater Seal of Vitality For more late game health and overall durability
or Greater Seal of Evasion Works like armor but dosn't befit your Spike Shell or Defensive Ball Curl but helps proc that little Nimbleness speed buff every now and then.

Greater Glyph of Scaling Magic Resist More late game MR (: I wouldn't take any other blues.

Greater Quintessence of Movement Speed Movespeed is always good.
Alternatives are:
Greater Quintessence of Magic Penetration If you decided that you wanted Greater Mark of Magic Penetration Reds over Greater Mark of Attack Speed to help boost it that little bit further.
Greater Quintessence of Health Moar starting Health to make you harder to kill early game when you are most vulnerable
or Greater Quintessence of Evasion If you happen to be a fan of Dodge. (:

I go for the ordinary 0/21/9. The defensive tree shouldn't be changed up too much but you can play around with your utility points or you could put them in the offensive tree to grab Archaic Knowledge

I try to get Heart of Gold as soon as possible so I start with a
Ruby Crystal as Cloth Armor is no longer in the recipe.
Once I get 700gold I b and finish my
Heart of Gold and buy Boots of speed.

Then your up to your first multi-choice Item selection. (:
Normally you would grab Mercury's Treads but in the rare occasion that your up against Master Yi, Tryndamere, Warwick and whatever consider buying
Ninja tabi instead.

Then we buy our Frozen Heart starting with the Glacical Shroud Glacical Shroud part first.

Then you could either build up your Thornmail or Sunfire Aegis
I personally build up my Sunfire Cape first as the Health it provides adds to my overall bulkiness more then a Thornmail does. But if you're having a hard time from a Master Yi or a Caitlyn you can go right for your Thornmail (:

Flash. I always go with flash on all champions (with the exception of those who already have a built in Flash like Ezreal). Its useful for escaping, chasing, posisioning etc. etc. Just an all round good spell. Wouldn't recommend taking any other.
The second spell though is entirely up to you.
My recommendations are:
Ghost
Cleanse
Heal
Teleport
Smite(only if jungling!)
or Fortify (:

Spiked Shell, Rammus's Passive. Gives him 1 extra AD per 4 points of Armor he has. This works nicely giving Rammus a nice amount of AD mid game. We gain 25 AD from Thornmail / Frozen Heart and 19 AD from Randuin's Omen. With our armor in the 400s late game we have 100+ extra AD just from our passive (:

Powerball! One of my most favorite abilities in the game. Besides the fact that with this you can achieve the highest movespeeds in the game it's such a powerful ganking tool. Just Powerball towards them, Knock them up and taunt them away from their tower/allies. (:

DBC. This is the reason you don't have to stack to much MR at all because with this you gain 150 points of it anyway., that's higher than the MR of 3 Negatron Cloaks combined!! On top of that it gives you 150 Armor and 37 AD (due to Spiiked Shell) and a Flat version of the Thornmail Passive!! All of that in a 10 second Cooldown (with the CDR we get from Randuin's Omen and Frozen Heart) and a tiny 50 mana cost! (:

Puncturing Taunt Puncturing Taunt. The longest Taunt in the game!! This is the reason no1 can push a tower as a duo when your around. Max this skill first.

Rammus's ult! Soaring Slam is a great AoE in teamfights on a relatively short CD (45 seconds). This well help alot when pushing towers. (:

Pros:
- Extremely durable
- Built in escape mechanism
- Longest Taunt in the game
- Powerful Ganker
- Strong Pusher
- Can jungle

Cons:
- Weak laning phase
- Easily kited
- Needs to b often because of Mana
- Sometime Blue buff reliant

So guys I hope you like it! Try it before you vote and any/all constructive feedback is welcome! ;)