Humorous science fiction

Retief	Red Dwarf	Expecting Someone Taller	Douglas Adams
Turn the dark cloud inside out	Smallworld	Beatnik Rutabagas From Beyond the Stars	The Snarkout Boys and the Avocado of Death
Johnny and the Bomb	Only You Can Save Mankind	Robert Adams	light fantasy
Young Zaphod Plays It Safe	The Stainless Steel Rat	Bill the Galactic Hero	Good Omens
Mostly Harmless	Tom Holt	The Fifth Element	The Hitchhiker's Guide to the Galaxy
Robert Rankin	Dirk Gently