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In the Vonnegut vein look at works by Tom Robbins, Tom Pynchon and Philip K Dick. Not all of these guys are science fiction but they share Vonneguts off beat, funny and intelligent style of writing.
 
The Wasp Factory by Iain Banks.

Best. Book. Evah.

Either that or The Hitchhikers Guide to the Galaxy by Douglas Adams it is required reading for everyone. Funniest book I have ever read.
 
Atlas Shrugged is a fantastic book... probably my favorite. If I recall it's about the same length as The Fountainhead and well worth the time. If you're looking for a quick read try Anthem. It was just as powerful to me as Atlas Shrugged but about a twentieth the length.

This thread lists MR user's favorite novels. Take a look through there and you might find something.

Thanks for the link. There's a lot of good stuff there.
 
I have one. I haven't finished it but it's remarkably odd.
A Confederacy of Dunces by John Kennedy Toole

The fact of this book is that "Toole wrote this novel in Puerto Rico during a hitch in the U.S. Army. In 1966 it was rejected by Simon & Schuster. In 1969 Toole committed suicide. Toole's mother then tried to get it published. After seven years of rejection she showed it to novelist Walker Percy, under whose encouragement it was published by Louisiana State University Press. Many critics praised it as a comic masterpiece that memorably evokes the city of New Orleans and whose robust protagonist is a modern-day Falstaff, Don Quixote, or Gargantua."

In the end he won a Pulitzer Prize for the damn thing.

I second this suggestion.

Also, read Lamb
by Christopher Moore. Then start back with his first book and read them through by published date. The characters cross over at times, so it's more enjoyable reading them in order.
 
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