EVE Online will be free for twenty one days on Steam for people to try out:
Not since the launch of Sputnik 1 (Спутник-1 for our Russian players) has an event excited so many would-be astronauts. It's an extremely rare victory to snatch a "first" in the MMORPG marketplace in 2008. However, CCP and Steam have managed to do just that. We want to remind you that EVE is the first MMO available on STEAM; they're even offering a 21-day trial as a special incentive to new users. See you in space capsuleers.
Have your friends check out the link above and sign up.