Looks like Xbox Live will be throwing some sales until the end of the year. Somewhat similar to the deals happening in Steam, each day until the New Year, Xbox Live will be offering special deals for games, game add-ons, and avatars, but the deal only lasts for 24 hours. gotta be quick!
You really have to be quick. Was only aware of this when they were on the second day, and first day had to be the game that I've been waiting to get a huge discount on. Xbox Live kicked things off with Bastion being 50% off on the first day. Can't believe I missed it.
The deals changes everyday so check regularly and maybe something will catch your eye. If you don't want to miss an awesome discount like me, check out this guy's page here. He works in Microsoft and will provide detailed information and announcements of the new offers.