Satoshi Labs is a faucet site that lets you reinvest your earnings to upgrade your "lab", and you get a certain amount per hour based on your "production". I haven't taken anything out yet, but rather just keep purchasing the "security" upgrade (part of the virtual game) to get more production. There's no way to put money into the site, but rather you just invest what you earn there. That's limiting, but it's also zero risk.

Since it's a positive feedback loop between "production" and earnings (more of one leads to more of the other, etc.), I figure that over time (a year or more) there could be enough to start making withdrawals. As with many faucet sites, there is, of course, the chance that they won't be around long enough, but at zero risk it's worth playing the little game. At least this is the best I've found since the end of the Mining Game on Cointiply.

I have a related post on my blog about faucets, etc. with my experiences and some tips.