Cheapest i've seen so far - there's a few other games cheap too!
DanceEvolution - Xbox 360 Kinect Game.
For use with Xbox 360 Kinect - requires Kinect sensor.
•DanceEvolution is an all-new concept where the game responds to real dancing, with Kinect for Xbox 360 demanding players move their body to the beat and position of their bodies against a variety of on screen markers.
•DanceEvolution will offer users the ultimate dance club vibe, and boasts the most realistic and exhilarating dancing experience to date.
•Kinect for Xbox 360 allows players to watch their actions in real time and also save two of their original routines for use as back-up dancers in the game, no controllers required.
•As players dance in tune to the game's music, they can also take snapshots of their favourite dance poses, save to local albums and share the fun with friends.
•Utilising Xbox LIVE for the Xbox 360 video game and entertainment system from Microsoft, players can also challenge up to four friends around the world and enhance their experience with dance sequences, theme packs and more.
•Featuring 30 tracks spanning club music classics, Hip Hop, R&B, Pop, and Techno, Dance Evolution dancers can groove to their favourite songs.
•The game also offers three game play modes for the ultimate dance experience: Dance, Lesson, and Status. In Dance Mode, users compete to become the 'Dance Master' as they play and unlock their favourite songs and dance along with a friend.
•Lesson Mode offers a tutorial service, and Status Mode allows players to check their play records and review the titles they have earned.
•Players can also compete to determine the ultimate dancer with multiple difficulty levels including Light, Standard, Extreme and Stealth.
•For ages 3 years and over.