The title says it all, folks: your favorite humorous novels.
I’ll start with Confederacy of Dunces by John Kennedy Toole, one of my favorite novels, period. I can’t read more than a page without cracking a smile.
Your turn!
Good Omens, by Neil Gaiman and Terry Prachett. Wet-your-pants funny.
I have learned not to read most of Bill Brysons stuff while riding on busses, or otherwise in public. It seems other people are taken aback by a person suddenly bursting into guffaws.
Other “Not safe for public reading books”:
Cosmic Banditos - A.C Wisebecker
First 4 books of Hitchhikers Guide - Douglas Adams
Got to put in a second vote for “Confederacy of Dunces”
Spike Milligan’s War Memoirs
The “Wooster” books (P.G. Wodehouse)
There are more…
Regards
FML
Anything by Pat McManus. I have never lived with anyone who didn’t eventually try to forbid me from reading Pat McManus after dark, beginning with my parents and brother at midnight the day I acquired “A Fine and Pleasant Misery.”
Twenty-some-odd years later, I still can’t even think about “…two naked and enraged people chasing a hysterical fat kid up the side of a mountain in a blizzard…” without dissolving into giggles.
See Pratchett, All.
My exact thoughts when I read the title to the thread. I have read all of his books at least twice. Every kid should grow up hanging around a mountain man named Rancid Crabtree.
And a dog named Strange. 
Well, shit. I came to mention McManus and Wodehouse but I see I’ve been scooped.
My fave McManus story is the one about the muzzle loader/canon. “What are you boys doing smoking behind this shed?”
“Geez officer, you should have seen us while we were still on fire!” (I’m guessing at the dialogue, it’s been a while).
And of course, anything starring Rancid Crabtree.
I consider them the Jeeves books 
, but it’s irrelevant. They’re ridiculously funny. I’m 1/2 through “Life with Jeeves” for about the 5th time - it’s a 3-book compilation, I think (I’ve actually lost the cover and 1st 12 pages through routine wear and tear).
Joe
“Budding Prospects” by T.C. Boyle
Just about every one of Obrian’s Aubrey/Maturin novels had me in stitches as well.
A Gent from Bear Creek by Robert E. Howard. Imagine Groo set in the Old West.
Nick Hornby’s High Fidelity had me pausing every few minutes to either laugh out loud, brood meditatively, or both.
Certain Dave Barry books are pretty funny. I liked “Dave Barry Turns 50” quite a bit.
I read Chelsea Handler’s book “My Horizontal Life” and was cracking up the whole time. She is just so wrong.
David Sedaris has his moments. I’ll catch a sarcastic line or something that just does me in.
Lamb, The Gospel According to Biff, Christ’s Childhood Pal
By Christpher Moore
I am re-reading right now.
Man I love this book.
I laughed my ass off at Catch-22 by Joseph Heller.
Just to echo some previous posters:
Count me among the McManus fans. He often brings me to tears of laughter. I think anyone could appreciate his stories, but if you’ve spent some time in the outdoors going hunting and fishing and camping then McManus is pure comedic genius. If all my books weren’t boxed up right now, I’d read a story or two before bedtime tonight.
And I’m working my way through Prachett’s books. I’m pretty much guaranteed many laugh-out-loud moments whenever I crack open a Discworld tale.
<gratuitous suck up>
Anything written by Cecil Adams…
…and I’m serious!
Dammit, Ludy! That was mine!
“Peter, you’re as dumb as a box of rocks…And on this rock…”
I third that.
I also like Robert Fulghum’s stuff. It’s not slapstick funny like McManus (whom I also like despite not liking slapstick) but there are some funny or ironic stories. I especially like Fulghum’s “It was on fire when I lay down on it.”
ETA: Oh yeah, and Bill Bryson is good too. I really liked his “A Walk in the Woods.”
I recently discovered Jasper Fforde. I laughed out loud at every one of his books I’ve read so far.
The Illuminatus! Trilogy and Schroedinger’s Cat trilogy have their moments.
Kurt Vonnegut is extremely funny in a very dark and cynical way. I recommend Slaughterhouse Five and Breakfast of Champions.
Terry Pratchett, of course. Anansi Boys by Neil Gaiman was quite funny.
Definitely Douglas Adams. Woody Allen’s Getting Even is excellent. That’s a pretty good start, I reckon…