I've actually wondered this myself. As a fan of comedy Shoujo anime like Clannad and The Melancholy of Haruhi, I've often wondered if there were any games beyond the typical uber-cheap Japanese dating sims. I think the thing with Comedy is that its all based on the delivery and is almost always tied in some way to dialogue or specific situations, both of which are somewhat questionable areas for video games: too much dialogue and people complain about the amount of it, and too many specific situations would require more cut scenes, causing people to declare a lack of actual GAMEPLAY. For example, look at Heavy Rain and Final Fantasy XIII. Both games are heavy on story and cut scenes, sacrificing traditional game play for heightened story experiences. The complaints those two games received are indicative of what reception would be like for a comedy styled game that didnt walk a fine line between setting up the gags and having great gameplay elements.
The closest to comedy games I can think of that worked were usually of the "Adventure" game ilk, most notably the heyday of Lucas arts point and clicks.. Sam and Max, Day of the Tentacle, Grim Fandango, Monkey Island... a few newer entries like Strong Bad and Psychonauts have done great things, but if you want comedy you need a way to present a story and deeper character development than most games are willing to provide. Battlefield Bad Company one and two had some pretty good comedic elements, but were mostly built on their solid FPS gameplay.
But the day someone combines a game like Heavy Rain with the comedic gold that was Excel Saga, will be the day that I become a devoted fan to that game studio.