Free Keys now (3000 left as of 7th): http://www.mmobomb.com/giveaway/warframe-beta-keys
I recommend you to check out the game Waframe.
Here is the first trailer:
Here is an overview of the game:
It is 3rd person co-oop free to play hack and slash rpg.
Basically the game plays a lot like Mass Effect 2-3 but faster, like Vanquish (pretty good PS3 game) and then you add in the free to play and hero picking and upgrading element like in LoL. It also has some Metal Gear Rising elements too it. Just look for yourself.
Right now there are only about 2000 players, and the 50 or so I have met, were not communicative at all. If there are ~4 players in a game the game becomes much harder and better (like in Serious Sam there are 4 times more enemys). Also I think every game gets better when you play it with someone from TL.
Right now i feel like it doesn't take long to get into the beta. If you invite 3 friends you get in faster, so maybe we should post our referal links, register via them until 3 guys did it and then move on to the next. Since I'm already in, we'll just start with the first one who posts.
Also if you get into the beta, be careful of your choice of Warframe (aka Hero) cause you only get the first one for free.