Even starship captains get the blues sometimes. And when you get depressed, or when you're stuck in bed with a nasty case of black plague, you need something to cheer you the frak up. Luckily, there are tons of science fiction and fantasy books with proven restorative properties.

For every movie that makes it to your local cineplex, there are dozens that never come into existence. In another universe, Mel Gibson directed Fahrenheit 451, Terry Gilliam directed Watchmen, and Batman fought Godzilla. The history of movies is crammed full of weird almost-weres and could-have-beens. A lot of people…