Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Why do you build a tank that has armor against Magic!?
Let me ask you something about Rammus. When you see him, he's obviously a tank. Everything he does says "HIT ME!" Well if you take damage, you should be able to give it back. His attack damage increases with armor, also making his ball curl more powerful as well. How you make ask, because the base damage you take, before reduction of armor + damage increase of the ball curls bonus damage, goes back to the enemy that you have taunted which in turn makes the damage hurt them more then it hurts you.
Why not stack Health!?
Easy counter, Madreds Bloodrazors(Attack Damage) OR Deathfire Grasp(Ability Power).
Why Level Taunt First?!
Laning with other CC types is a grand idea early game, let them push into your turret allowing you to have access to the defensive strategy at level 9, unless they have Mercury Treads, they will come with for 3 seconds and will be forced to stand near the turret till your teammate locks then into place.
Best laning partner is Singed for his toss. Toss into turret taunt, half the work is done before it starts it's 3 second duration. Goo in his path for escape and BLAM done.
Why play a champ that gets banned in ranked?
I stopped playing when I found out he gets banned in ranked, BUT I till play with him when my team needs a tank to carry.
This is my honest to goodness first guild, and I thought doing my Rammus build would make a good test drive. I hope you like it and hope it turns into the better builds you use for him. I have gone 15/3/30 before with him, I have even gone 20ish/0/10. I have even had bad games with him where I've gotten 10/13/28, but it's all on how to survive.
Knowing when to run is the best part of being a good tank. And knowing when to sac yourself for your teammates that way they can get away and kill them off later is also a noble thing to do. Keep in mind you are not invincible, but it will take a lot to kill you.