Warframe is an upcoming Free-to-play co-op game. This game is still in BETA mode, but it looks really cool and if you "become a founder", you can play the BETA's. There are different levels of founding, the more you pay, the more you get of extra stuff. I personally just bought the "Disciple" version which is the standard one.
Anyways, a Warframe is a kind of space ninja. Think Raiden (Metal Gear Rising) + Zer0 (Borderlands 2) in a kind of Mass Effect world. It's an FPS (all sorts of guns) with Melee fighting (sword, staff, gauntlets and such) and some special abilities (kinda like magic). There is a Solo mode and a Multiplayer mode with up to 4 players in one team, kinda like Borderlands or Diablo 3.
There are alot of different kinds of Warframes (3 to choose from at start, the rest can be bought) which each have different abilities and playstyles. There are lots of skilltrees to choose from, lots of abilities to upgrade your character with and you can even re-colour your character. As you play, you earn credits to buy your upgrades with or other weapons.
So yeah, if it interests you, then I would definately recommend it. ^^
