Gamefly has a great introductory offer for Xbox 360 owners:

Get 400 Microsoft Points FREE plus 60% off the first month!

• 1 Game Out:  $5.95 Plus 400 MS Points ($15.95/month thereafter)
• 2 Games Out: $9.99 Plus 400 MS Points ($22.95/month thereafter)

Check it out:  Gamefly Xbox 360 Deal