Freebitco.in

http://freebitco.in/
This is a great site. Once you register, you're able to 'play the game' every hour, which gives you a shot to win free bitcoin. Playing the game consists of entering a captcha check, which rolls the dice, and wins you either a small (or large) amount of bitcoin. It seems as though most of the time when you roll, you win a small amount of bitcoin.