Hello,
I haven't seen this one build for Urgot yet here (or haven't just looked far enough :-P). I haven't invented this build - I saw some people using it, and I have to say it works quite well.

Main Urgot problem, is that he sucks pretty much at the end game. This build, makes him a bit weaker in the beginning (when he is quite strong, actually), and makes him rock in the endgame. This stats meter doesn't include damage from Atma's and Manamune.
As in fact, this amount of health and mana, is about 400 dmg in endgame.

For the item choice, depending on your enemies, you can switch Trifocrce and Frozen heart for something more fitting them. If they have massive AP - get FoN and Banshee's. (Funny thing is, that with Atma's and Manamune, Banshee's gives you bonus 15 dmg. Pretty cool, eh?)

As for spell choice, I put in ones I'm using. I love teleport, flash - not that much, but it is usfull at the beginning, when you are not-so-tanky-yet.

And lastly, the masteries choices. If such item setup, you are going to be pretty tanky anyways. Bonus dmg masteries, make bonus dmg from Atma's and Manamune do wonders.

The best thing about Urgot, is that you can pick any lane, and farm effectively.

Once again - I DID NOT INVENTED THIS BUILD, (honestly, I don't know who did). Who ever he was - all credits for him.
If anyone will like it, I'll expand it a little bit more.
Sorry for my english, ain't that great :-X. (If you can, give me some tips about correcting the mistakes).