Super Mario RPG comes to mind when it comes to a game making me laugh because of Dialogue. When Mario is about to face MACK (the first boss) one of the Bosses goons talks trash to Mario by saying "How about a fat lip to go with that Ugly Mustache?" OR When Mario went at Bowyer (2nd Boss) Fist Flying and Mallow tells him "Who do you think you are? Bruce Lee?" and stops him. Booster the villain, the cake that's alive, and when Mario is expecting a kiss from Peach and instead gets kissed by Bowser and Booster are all classic moments of gaming in my opinion. These are just a few of the many funny examples in the game...
Others examples of funny was Project X Zone with the Anime Guys flirting with the Anime girls (and many girls flirted with the guys are well!). GTA IV was pretty funny when it wasn't violent. But most recently I just find myself grinding the majority of the time playing recent Mario games (NSMB2, SM3DL, MK8). The stages, music, and atmosphere just get to me all the time...
