I think Lego Star Wars 2 The Original Trilogy was one of the games that I got the most laughs out of.
Lara Croft and the Guardian of Light. Not that the story was funny (though the dialogue was lulzy) but my brother and I were laughing so hard cause the co-op was so much fun.
Umm..... I think it was a few years ago when i started Playing the Legend Of Spyro Series. Tey editied one of the charaters to make him talk, all he said was funny :)
Little big planet, I enjoy watching the sack person facial expressions and what happens when you punch other sack people xD But also when my friend first played it around my house we ended up laughing for ages because she pointed out how funny there little legs look when their dangling off something an how much she failed on the levels.