Not sure about laughing out loud but here are some of the games I found witty or I found humorous-
Quest for Glory games
Lunar 1 and 2 (Working Design translations were what made the tedious battles worth going through...)
Perhaps Jade Empire and Dragon Age Origins
Probalby others forgot about...
(and yes I realize Nier and Planescape: Torment are also extremely depressing games in some senses but they are also both very funny at points especially Nier.)
I keep getting ninja'd! D= (*sings* Baaaad luck to be meeee...)
Bard's Tale is frikkin' awesome. I wish I still had my old xbox so I could play it, sigh. Portal 1 & 2 could probably share second place. Oh and I giggled all through Simon the Sorcerer 1 & 2 so they can share 3rd =P