MMO Betas are like your way to apply to be in the "cool club." Today is the day you put on your fancy pants, pop your collar, and attempt to understand what the hell a Ke$ha is. Guild Wars 2 is having an open call for beta participants, the game is attempting to redefine what it means to be an MMO. Instead of grinding and meaningless kill 10 rat quests, the game promises a strong focus on story and character development.
Of course, like any MMO, the game will be strongly co-op focused. Best of all, there will be no monthly fee for the game. So if you wanna try your hand at being one of the cool kids, head on over to the beta site to sign up. Just a note, you'll need to sign up from the PC you plan on playing on - as it requires a small download to run some system checks.