Most humorous game youve played...

[Jin]

I'm surprised none of you mentioned Conker's Bad Fur Day.
It's quite possibly one of the funniest games ever.

If childish jokes about excrement are your cup o' tea, perhaps...
Let's face it, Conker's Bad Fur Day was only funny at the time because A) we were kids and B) that kind of content in video games was extremely controversial when it was released. Looking back at it, the humour looks as if a 12 year old came up with it.

As the OP stated, Uncharted 2 has a great sense of humour. It manages to be adult without resorting to excessive profanity and comes out all the better for it. The first one was good for this as well.

Any game by Tim Schafer tickles my funny bone. Brutal Legend, Full Throttle, Grim Fandango and of course, Monkey Island. All classics.

There are some others I can't think of at the moment. I'll post them later if I remember.