I just tried areyouahuman.com, but it's very slow to use from a user perspective.  It's almost as bad as confidentcaptcha (which http://jackpotfaucet.com/ uses).

Are there any faucets still using this captcha? http://demo.minteye.com/Demos/TestSlider180.aspx
I remember seeing them a while back when I first discovered bitcoin and now that I'm ready to create my first faucet, I want to find one as an example.  I want to use MintEye because it has occasional ads inside the captchas which pays the site owners and Recaptcha and SolveMedia can serve illegible captchas if users fill out too many of them.