www.keepingittwisted.com
direct link:
http://www.keepingittwisted.com/xbox_promo_landing.aspx
only works with americas market place.
so for you uk people like me just make an american account when you want points and then buy what you want, you'll be able to play the content on your main account...
when your doing this you click make new account, type in random stuff...
Screen name: awjoifj
email:
naoga@kjakj.com
password: d
then submit it...
it says sorry but here have a complimentry free 48 hour trial for xbl...
or it says...
congratulations! you won 100 free ms points!
Takes time but its free so...