http://giveaways.bundlestars.com/
You have to sign in to Steam through their website (I'm not sure exactly what that does or means) and give them an email address.
Quote from: http://giveaways.bundlestars.com/
In association with the developers Might & Delight we are giving away a FREE Steam key for the highly acclaimed Pid (SRP $9.99). Just follow the instructions to the right and the game is yours to play.
You have to sign in to Steam through their website (I'm not sure exactly what that does or means) and give them an email address.