The Foursquare badge names and "descriptions" are supposed to be whimsical I guess because they aren't very helpful in figuring out how to earn the badge. So how do I figure out how to earn a particular Foursquare badge? What's the best way or source of information?
As phwd states in a comment, there is no official source. However, an unofficial page lists Foursquare badges with instructions for getting the badges. There's no guarantee on the list being correct, but as Foursquare doesn't officially reveal the criteria, so it's probably your best bet.