Found this [link] and thought I'd share. I have about 60 of them and got 100 MS Points so far. xD

1.First go to this link: [link]
You should see a registration form.

2.Now you create a screen name and email address (email doesn't have to be a real one.)

3.When it asks for the access code enter: AA4XPN3
You can use this over and over again, then enter the image verification and hit "Let's Play."

4.Now if you were lucky you will get some free Microsoft points, a faceplate, or even a free game. If you get a game, just enter your address and no name or email is needed. But usually you'll end up with a code. That is your free Xbox Live gold for 48 - hour code.

5. Repeat as many times as you want, just be sure to change the email address each time. Each code can be redeemed as a promotional code on your Xbox Live membership.

NOTE: This only works on existing Gold memberships.

Have fun.