Castle Crashers is live on Steam right now for your adorable medieval animal orb pleasure, for $15 on PC and Mac. Since Castle Crashers launched in 2008 and is on both XBLA and PSN, the Steam release directly benefits staunchly anti-console gamers and those with a "don't play a game until it's been out for four years" policy.
For those in either category, or for anyone looking to grab a free copy of Castle Crashers on Steam, stay tuned to the Joystiq Twitter account (Officially Verified!), where we'll be giving away free codes. Good luck, valiant Steam knights.