What foods and beverages stain teeth?

Dark things. Coffee, tea, soda, red wine, chocolate, any dark foods and beverages.
Lots of things... Common offenders: coffee, black teas, tobacco, wine, excess amounts of berries (blue, black varieties), sodas. Acidic drinks (including things like sports drinks) can damage enamal and set you up for tooth stains. A good tip: use a straw for drinking so that the front teeth aren't as exposed the liquid.