Before your read all this:

Please keep in mind to never rate a guide before trying it out first, unless you've already tried it.
This is a pure tank build. If you aren't good at tanking, don't rate at all.


Gragas Changes:

• Dec. 13, 2010 - Heavy Nerfs:
  I don't think these were deserved. Gragas wasn't as viable with the AoE Metagame in place. But that got nerfed. Ingenuity made the Locket Gragas immortal, but Locket is now removed!
  Gragas isn't nearly as Tanky-DPS as Olaf, or Udyr, yet felt the greatest brunt of the Tanky-DPS nerf-bat...
• Drunken Rage damage reduction reduced to 10/12/14/16/18% from 10/14/18/22/26%
• Drunken Rage mana restoration changed to 40/55/70/85/100 from 50/60/70/80/90
• Explosive Cask cooldown increased to 90/75/60 seconds from 60

Updates:

• Dec. 13, 2010 - v1_0_0_107 - Innervating Locket has been removed!!
  Therefore, I will be archiving this guide until further notice. I hope you all enjoyed it while it lasted.

• Dec. 12, 2010 - Added #4
• Dec. 12, 2010 - Added "Spirit Visage" to core item choices. I've removed Banshee's Veil completely, as I've deemed Force of Nature to have much better synergy with Gragas.
• Dec. 8, 2010 - Added the #2 and #3 to the "Ten Tips to Tanking!"
• Dec. 5, 2010 - Added the #1 to the "Ten Tips to Tanking!"
• Dec. 5, 2010 - Added a youtube video that demonstrates tanking very well. (Skip to 5:40 in it)

Introduction

Due to Innervating Locket's new rework, I noticed that it had insane compatibility with Gragas' Happy Hour and Drunken Rage Drink effects.

It bears great resemblance to the usual first choice of Gragas players, Rod of Ages. And, since this is a tank build, the loss of AP can be negligible.
The synergy it offers with Happy Hour makes Gragas the best kiter in the game!

Summoner Spells

Exhaust.

As an AP Tank or Pure Tank, his CC isn't all that impressive. Body Slam sends you out of the frying pan and into the fire, and Cask is very hard to use correctly.

Exhaust will ensure that your enemies are crying inside as your team rips them apart.

Ghost.

Gragas already has a dash skill that can let him pass walls and heavy damage spells.
Ghost will satiate your need-for-speed after your pull off Body Slam, and need to run around the field.
Fat men walk fast, they don't run. :3

Runes and Masteries: Tank style

Magic Penetration Marks, standard.
Dodge Seals, I like these because being a melee means I tend to draw a lot of minion aggro. It also reduces the chance I could get killed by a stray auto-attack.
Flat Magic Resist Glyphs, a nice chunk of MR so you can keep chugging down your drinky-drinks even with enemies unloading spells on you.
Movement Speed Quints will let you chase down enemies and farm much more efficiently.

As for Masteries, the utmost importance goes to:

Sorcery, Awareness, Intelligence
Getting a level advantage is very important, at the very least you want to keep up with your enemies who will also often be bringing this mastery into play.
With only 7 points in Offensive and Utility, you can leave the spawning pool with 9% CDR, all the better to pop more drinky-drinks! :)

"Presence of the Master"
The top tier Utility mastery is a simple Summoner cooldown reducer.
Nice to know you'll have Exhaust and Ghost up more often.


Quickness, Archaic Knowledge
Basic stat boosters that will really help you put the hurt on creeps and enemy champs.

Skills and Ordering Justification:

Barrel Roll:

By far one of my favorite harassing abilities.
With a range of 1000, you can cut down enemy HP without taking any damage yourself, as well as farm effectively.
You max this first as your main damage output.

Drunken Rage:

Better known to me as my Drinky-drink.
With a duration that can match its cooldown now, you can stay drunk almost 100% of the time. Free mana, attack boost, and damage reduction makes this a glorious spell.
Focusing on this second is essential to keeping Gragas happy and violent. >:)

Body Slam:

Gragas's notorious for being a big BIG man.
This skill thrusts that statement straight into enemies. Though, it can also really screw up people's intuitions when he uses it to pass through walls in-game.

I only get this once at level4 for escape purposes.
Compared to your Barrel and Drink, it's not a very good laning-skill, so best saved for later levels.

Explosive Cask:

This skill... It can make or break a team fight and takes massive skill to use properly.
Half the time it will be less useful then Nunu's Ultimate; justifying claims that Gragas is not a reliable tank.
However, being on a very low cooldown and being quite the effective nuke keeps it a useful part of your arsenal.

Happy Hour:

One of the best passives in my opinion. With a low Body-Slam cooldown, Happy Hour procs can even save you from Ignites and DoTs. When laning or kiting, this can render you almost-immortal.

The combination of Innervating Locket will turn that "almost-" prefix into "semi-"! >:)

Core Items:

Start: Mana manipulator.
Keeping in mind that you want to rush the Innervating Locket, this mana aura can be good for a lane-partner, as well as let you Barrel Roll more freely.

Boots of Speed after, they are the standard 2nd item in any item sequence.

Innervating Locket: Now, let's examine what happens when you rush this little beauty.
With every cast, you heal 50hp and 20 mana. Combo that with Happy Hour (40~60 HP) and you're recovering 110 HP every 5 seconds with enough ability casting.
The mana-regain covers over 20% of your regular mana-use, with Drunken Rage's regular drinks, you'll never have to Recall.
In lane, it means you're immobile, if they can't kill you, you can't be pushed out.
In late-game, you can kite like a beast, not even Teemo shrooms can stop your healing.

And never forget that the aura will make all your allies feel at home when hugging a turret as well. :)

FunThought: When I first thought of how much regeneration this would offer, RickRoll song lyrics started playing in my head.
Cause, I'll always be there to lane with them! :D

To enemies:

Never gonna give you up...
Never gonna let you down...
Never gonna run around and, desert you~
-Gragas.

Finish Boots: Mercury's Treads are standard, because of the insane amount of CC that's coming out.
If there's seriously a need for it, opt for Ninja Tabi.

Spirit Visage: With an extra 20% healing, your Happy Hour will be magnificent.
The HP, MR, and CDR shouldn't be ignored either.

Sunfire Cape: Your first true Tank item.
This will compensate your lack of AP, and seriously ramp up your farming, which is already quite impressive.
Please note that Sunfire cannot be exchanged for something else. You NEED the AoE damage it offers, otherwise your damage output will be invariably hurt.

End Game Items:

Now, the items you choose really depend on the enemy, since you're a tank.
The choices vary between countering AP, AD DPS.

Force of Nature.
If they're packing lots of AP stackers and nukers, get a Force of Nature.

This item is perfect, as it will FURTHER boost your healing to ridiculous levels.
If you start kiting, you're practically immortal! No near or semi, you ARE.

Randuin's Omen
If its DPS that is your bane, get Warden's Mail and work on an Omen.

Both the passive and active can really wreck a DPS champion's damage output. On top of that, you'll be receiving a nice 15% cooldown reduction, giving you a grand total of 25%!


Purchase the opposing item as your 6th item if the enemy team is balanced.

Abyssal Scepter.
If the enemy strengths lie solely on AP, get this scary little item.

On top of boosting your AP a bit, it offers a Magic Resist reduction aura that will make both your alcoholic abilities and sunfire cape hurt more.

Thornmail.
If the enemy is hardcore AD devoted, this will give you a laugh.

Boasting 100 armor, and a near OP passive, you'll be thinking to the enemy: "Go ahead, kill yourself."
This item calculates damage returned using the true-damage over the normally-reduced your receive, meaning you'll actually be returning 40~50% of what they can deal to you most of the time.

Ten Tips to Tanking!

1. You (or the enemy Tank) should always be the trigger to the fight.
   It is ideal that you start the fight, and be the first one to enter. This means exposing yourself to the majority of enemy spells, so your allies can fight freely.
2. Be Patient and use the enemy mistakes for initiating!
   Too many times do I see tanks rushing in, and expecting carries and nukers to follow them. Unless you're really fed, patience is key, don't risk putting yourself in the enemy's rhythm in fights.
   • Skip to 5:40 at this video and you'll see what I mean by "patient."
3. When initiating, go for the Carry!
   Also demonstrated by the video clip, when you see an opportunity to initiate, it should be because the enemy carry messed up. Make a B-line for the carry, so that he/she can't fight properly, allowing your own carries to focus on squishies or the carry.
4. Communicate and be the leader!
   Be sure that your allies understand points 1, 2, and 3. Take charge, and make sure you set the rhythm for the team fights that are predictably about to happen.
5. (Under Construction!)
6. (Coming Soon!)
7. (Under Construction!)
8. (Coming Soon!)
9. (Under Construction!)
10. (Coming Soon!)

~ ~ Final Comments ~ ~

Gragas isn't the best tank, but he is certainly one of my favorites.
With an far-reaching skill-shot and the best self-buff skill (the drinky-drink) in the league, he's one of the most fun champions to play.

Though he needs a little tweaking to be appreciated by higher ranks, I think this tank build does Gragas justice.

I hope this guide was helpful. If you see anything wrong with it, leave a comment and I will try my best to justify myself or fix it.

Good luck and have fun, Summoners!