There aren't many things better than free video games and, by signing up at GameFly.com, you can download a copy of the original BioShock at no cost. Normal retail price for a digital copy of the 2007 title is still between $5-$10 so getting it absolutely free is pretty awesome.
The only catch here, if we can even call it that, is you'll need the GameFly client (similar to Steam and Origin) to download and install. Some forum members have also mentioned you'll need to enter billing and credit card information which is strange given this is a free download. GameFly is a reputable company though so we don't expect you'll get charged but just keep it in mind. For a highly rated game, we'll take a chance on it.
The game is available for download and is rated M for Mature.