Warframe is a 4 player co-op game that has randomly generated missions, with the usual weapon unlocks, mod unlocks, special abilities, and classes to define your character. Oh, and you get ninja sword if you want to get up close and personal. It is being work on by Digital Extremes, developers of known games like Darkness 2 and Dark Sector.
I don't know what to expect with Warframe just yet but I'm quite curious to see how it plays out. It's something new in a way that - It's Free-To-Play, looks amazing for a free product, and is mainly focused in 4-player cooperative play. It's currently on closed beta, but just for February 15-19, non-beta key holders get to have a taste of Warframe. I'll be downloading the client once I'm allowed to do so and we'll see how it goes.
If you want to join the open beta event, go ahead to the Warframe website and register. The client should be available for download on Friday at 12:00PM EST, which is 5PM GMT on a Saturday in the Philippines.
[source: Warframe official website]