taken this from anotehr site so big shout out to pavillion..
1.First go to this link http://www.keepingittwisted.com/xbox_register.aspx
You should see a registration form.
2.Now you create a screen name that is the same as your email so you can get many codes. The stupid people who made the site didn't even make it check if the email is real or not. So go ahead and make a fake name. ie: [email protected]
3.When it asks for the access code enter:AA4XPN3
You can use this over and over again. Then enter the captcha and hit "Lets Play:"
4.Now if you were lucky you will get some free Microsoft points or a faceplate or game. If you get a game just enter your address and no name or email is needed. But usually youll end up with a code. You know what to do: highlight and copy it.
5.Open up notepad and paste your code.Keep this text file!
6.Navigate back two pages to the registration in step 1. Enter your info again but this time with a number. ie:faker1, [email protected]
. Use the same password to make it easier!
7.Keep going and collect the codes in your text file.
Each code is for 48 hours of Xbox 360 Live
If you do win a prize that they need to send to you (game or faceplate) then I think you need to live in the states as you have to enter your state and zipcode
he says he spent an hour and got 50 codes giving him 100 days..
not tried it as dont use xbox live but may be of use to others...