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.

Bitcoins 4 Me

Enter your bitcoin address and pass a captcha check, and you'll get a small amount of bitcoin.

CoinAd

Another simple free bitcoin site that requires passing a captcha check.

Daily Bitcoins

Despite the name 'Daily Bitcoins', this service gives you a small amount of bitcoin for free every hour.

Free BTC Net

A simple hourly Bitcoin payout site. Like some of the other sites listed here, all you need to do is fill out a simple captcha check to claim a reward.

Free Bitcoin Faucet

Another simple hourly bitcoin site. You can earn 40 microbitcoin per hour after completing the captcha check.

Half Daily Sites
BitcoinAR

After passing a simple captcha check BitcoinAR will send you a small amount of free bitcoin.

FreeCoins4Me

Like many of the other free bitcoin sites, freecoins4me gives you a small amount of bitcoin once you pass a captcha check. Right now you can come back once every 8 hours to get a small amount of bicoin.