TWRoO on 10 March 2009
I don't know which is funniest, but I shall list a few I remember laughing at.
Chibi Robo (also very sad in places)
F-Zero GX (the story mode has laughably cheesy script/voice acting)
LoZ:Windwaker (specifically the French guys on spectacle island/windfall)
TimeSplitters 2
Banjo Tooie
GTA2
GTA3
GTA VC
Batallion Wars 2 (the stereotypes of various countries military leaders)
No More Heroes
LoZ: Twilight Princess (some of the characters)
Zack and Wiki.
Oh, and I laughed pretty hard when I poked my Mii in the crotch on the Wii Play menu 
