The Stainless Steel Rat by Harry Harrison
The adventures of Slippery Jim diGriz (the Stainless Steel Rat) will take you all over the galaxy in this light-hearted and thrilling series. Though it reads like it was written for teens, adults can also enjoy the twists and turns. You never know what to expect next, but you soon learn to trust that the Rat has things under control. Or does he?
Hilarious, sarcastic, and wonderful fun. Part of a long series, but the first few are some of the greatest comedies I've ever read.