NetLookup

NetLookup is a simple free bitcoin site. Just enter your bitcoin address and they'll send you some free bitcoin -- no captcha required.
BitHits

BitHits gives you a small amount of bitcoin -- no captcha required.
DrawBTC

DrawBTC is one of my favorite sites -- you enter your Bitcoin wallet address, and have a chance to win a certin amount of Bitcoin every day. You're not guaranteed to win, but the odds aren't bad!
Bitcoin Addict

Enter your bitcoin address and solve a captcha, and you might win the daily jackpot.
Bitcoiner

Enter your bitcoin address and solve a captcha to get a small amount of bitcoin. The payout varies by the hour.
Bunny Run

This site lets you pick a bunny in a virtual race, and pays you a small amount of bitcoin depending on which place your bunny comes in.
Coin Ticket

Receive a small amount of bitcoin by entering your bitcoin address and solving a captcha.
Bitcoin Tree

Like some of the sites above, Bitcoin Tree gives you a small amount of bitcoin after you pass a captcha check.
HartCode

Vote for your favorite wallpaper and receive a small amount of free bitcoin.