Anything Vonnegut is good. I've read Slaughterhouse 5 and The Sirens of Titan, and I enjoyed both.
Let me make a different suggestion.
A play, by Tom Stoppard, Called "Rosencrantz and Guildenstern are Dead"
It is one of the funniest thins I have ever read. It tells the story of Hamlet through the eyes of his 'friends' R&G. They are rudely awakened one morning and sent, by the king to spy on Hamlet. However, Instead of the oily sellouts they appear to be in Shakespear's version, they are two unimportant people trying to figure out where the hell fate is dragging them and how to escape it. It is a great play if you like the idea of tragic heroes with the fates set against them. Sad, by terrifically funny.
Equally good is the movie version, although I only saw parts of it.
Hmmm, what else . . . . . You have read Catch-22, right? If not, pick that one. If you enjoyed it, you MIGHT like Something Happened. Its a long and tough read, and very, very, very depressing, but I thought it was an incredible book. Very funny in some places, but, on the whole, the narrator is majorly depressed by everything. Go to the library/bookstore and read the first chapter to see if you'll like it.
If you can get it past your teacher, I'd suggest Cryptonomicon by Neil Stevenson. This is certainly one of my top 5 favorite books ever, although I'm not sure if it has enough 'literary merit' to use for a class. Even if its not your topic, I would suggest that you read it.
Thats about it for now.