This is my first post, just sharing some useful info with you that could save you some money :)
Firstly My Sims - Skyheroes is £13.15 on amazon - pretty cheap for a new game, even though its not a great game.
Secondly, is the method I used to get Assassin creed brotherhood for only £26.30, this will work for any of the latest chart games as of 4/12/2010 (til an unknown date) though.
Here is the trade in list for Smyths for xbox 360, as found on their site: http://www.smythstoys.com/pre_played_games.aspx
Castevania Lords Shadow
Dead Rising 2
EA Sports MMA
Fallout New Vegas
Formula 1 2010
John Daly Pro Stroke Golf
Kung Fu Rider
Lego Harry Potter
Madden NFL 11
Medal Of Honour Limited Ed
My Sims Sky Heroes
Spiderman Shattered Dimensions
Tom Clancy's Hawx 2
Toy Story 3
WRC FIA World Rally Championship
Notice how My Sims - Skyheroes is in that list ? ;)
This is why you buy 2 copies of My Sims - Skyheroes and trade them in instantly and get a new chart game.
I did this today in Smyths Cardiff store, and now i'm playing AC :)
Abuse it until they notice this "mistake" (if you want to call it a mistake.)
I'm sure many people could use this method to save some money on buying xmas pressies. Good luck.
DISCLAIMER: THIS METHOD WORKED FOR ME, THE SMYTHS TRADE IN OFFER MAY CHANGE AT ANY TIME, I CANNOT BE RESPONSIBLE IF THIS DOES NOT WORK FOR YOU FOR WHATEVER REASON, SO ITS YOUR RISK, I'M JUST KIND ENOUGH TO SHARE MY OWN METHOD WHICH WORKED FOR ME :)