Fancy yourself a fan of playing awesome PC shooters online? Boy howdy, do I have a story for you: Developer Hi-rez Studios has released every game in its Tribes series for free on its website as part of the franchise's 21st birthday celebration. That means everything from Starseige: Tribes to the free-to-play Tribes: Ascend is available right now, gratis. And you don't even have to buy it a drink -- the party's on Hi-rez's dime! As if you had any big plans for this weekend anyway.