Bill Bryson has some funny books. Monty Python has some too. You'd have to preview them ahead of time so you may have to be selective. Still, we're not talking George Carlin here.
I think Roald Dahl's The Witches is pretty funny and some of his other books. He had a twisted sense of humor too.
My ds7.5 personally loves Gary Larsen but it is a particular type of humor and doesn't necessarily appeal to everyone. Then again, the same could be said for the Captain Underpants series, which is a particular type of humor and doesn't necessarily appeal to everyone either.
