"If I would've stopped smoking cigars when my doctor told me to, I would've never made it to his funeral." - George Burns
"Illegal aliens have always been a problem in the United States. Ask any Indian"
- Robert Orben
"I bought a dog the other day... I named him Stay. It's fun to call him... "Come here, Stay! Come here, Stay!" He went insane. Now he just ignores me and keeps typing"
- Steven Wright
"A woman drove me to drinking, and I haven't had the decency to thank her." Churchill
Here are some others and this site has tons:
http://musicfolio.com/quotes/sarcasm.htm