This is not a long guide so i hope you read it all. This build on Rammus has done wonders for me. I won 20 out of 23 games.

Marks: Because it helps your q and ult do more damage, and because i think it is the best runes.
Seals: Because you need them for damage and it helps your jungle.
Glyphs: Because you will die if you gank mid without them...
Quints: Helps you get more items.

Standard tank runes. No s****er why i get them.

Before you go: "WTF is this ****?" I want you to think what your team can do with this. 1. you can have a bruiser top and a wota mid user and still have the double wota. In team fights you will heal sooooo much, because your team hopefully has double wota and you have spirit visage. With your AoE ult, people can't kill you. And because of you 25% CdR you can spam yout abiltis all the time. The best team you can have with this rammus build is: Kennen mid, Olaf top, Cait and Sona bot. The reason is because you and Olaf will go in like menn and tank everything, while you kennen comes after a while. Maybe a Sona ult has hit alot of them? And Cait, with her long range, can just stay in the back and kill everything. I have done this in 5 games with some of my friends and the team fights went all the same: 1 for 5 ace or maybe a 0 for 5 ace. We just had so much cc and a carry they could not get to. One game they had a Jax and he always jumped on the cait, but when he got there he hit her once and he was dead.

Smite: Because you jungle.
Flash: Because it is always good to have flash.
Ghost: I have tried it, but flash is almost always better, because you get such and early Shurelyas.

Start at wolfes, but you need to get some hits at them. If you don't get hits on them, you should start cloth armor and 5 pots. After wolfes do the blue golem, a good leash would not hurt at all. Then you do wraiths, Rammus does not take **** from wraiths. Do wolfes again and gank! You now have every skill. A gank mid will help your mid lane a ton! If you don't get first blood, go do your jungle again. First buy should always be a philo stone.

This guide is very short, might have something to do it being my first guide. I tried this once for the lolz and since that day this is the only build i run on Rammus, and it is very good.