If you're a gamespot member (if not, sign-up!), you can register yourself for a code that will unlock the Initiation Station demo (Saints Row: The Third) thing, for free.
Just sign-in/sign-up, and fill out the little information thingie after clicking on Xbox 360. You'll then get a code to redeem for the Initiation Station download.
http://uk.gamespot.com/event/codes/saintsrow-xbox/" rel="nofollow" target="_blank