I like Douglas Adams’ works. He’s about the only funny author I know of (which isn’t saying much, I’m not that well read).
My sense of humor banks heavily toward shows like South Park, Curb Your Enthusiasm, Reno 911!, The Daily Show/Colbert Report - in that order (movies: Office Space). I know that writing doesn’t convey humor exactly the same way as an image, but there has to be some good humor writer out there I would enjoy.
Do you like Dave Barry at all? I’ve read several of his books, but I have to do them in short bursts, because after a couple of chapters, I hurt from laughing. I don’t know how you feel about him, but he cracks me right up.
Seconding Terry Pratchett, and suggesting Carl Hiaasen. Hiaasen’s humor tends to be rather dark, so if you like seeing bad guys getting screwed over in humorous ways he’s a good choice.
Another vote for Terry Pratchett, skip the first couple of Discworld books and try Guards Guards if that doesn’t make you laugh out loud then maybe he’s not for you and maybe there is no hope for you
Bill Bryson, though not all his books are humourous. Down Under is.
I highly recommend Lamb: The Gospel According to Biff, Christ’s Childhood Pal. One of the funniest books I’ve read. Practical Demonkeeping is good too… er, it’s all good, really.
John Hodgman, The Daily Show’s “resident expert” and the PC from those Apple commercials, wrote a book called “The Areas of My Expertise”. It’s supposed to be an almanac, but everything in it is completely made up, so it’s fictional in a way, but it’s not a story. There’s a lot of stuff about the Hobo Wars and Werewolves, for example. It’s dry, but if you like TDS, I think you might enjoy it.
Another vote for Terry Pratchett, and as you are a fan of Douglas Adams I would also suggest giving P. G. Wodehouse a shot. I may be remembering incorrectly but I believe that Adams reffered to Wodehouse as one of the greatest satirical authors of the 20th century (if nothing else I know he admirred the man and his humour).
Others not mentioned - Canadian Mordecai Richler, banned South African now Englishman Tom Sharpe, Philip Roth - *The Great American Novel * got me into baseball, all of Bill Bryson is laugh out loud funny, Carl Hiassen if you like thrillers or maybe Kinky Friedman.