There have been tons of great deals in Kinect games lately. Best Buy has tons of games on sale this week. They also have an online-only deal with Kinect games as well!
Buy 2 Kinect games (some of which are already discounted 10-15 bucks) and get a $10 gift card! This deal is good through tomorrow. ONLINE ONLY.
You can also shop thorough Shop At Home to get 2% cash back on your purchases! Some other sites say that video games don't count toward cash back, but it didn't mention it on the Shop At Home site, so be prepared if it doesn't work, but at least try!
If you're new to Shop At Home, you'll also get $5 for signing up!