Right now - Dance Central and Your Shape Evolved 2012. Mmm also I hear sports is good - either version.

Unfortunately a lot of the early ground games have really poor reviews around their recognition. Sports andDance Central were both Microsoft ttitles so they are excellent. Your shape evolved (the first one ) was so-so and I've heard UFC is so so. Any of the 2nd round games coming out (the new zumba game in feb for example) should be much better. Also pretty much stay away from Wii ports.

This is based on me reading tons of amazon reviews not playing all these, but poor recognition is REALLY frustrating.

I play Dance Central, Your Shape: Fitness Evolved and Zumba Fitness with my Kinect.
Dance Central is excellent, it's a good workout with different difficulty levels and the game recognises you really well.
The other two are good games but they sometimes find it difficult to work out what you're doing and doesn't pick you up sometimes, it's a bit annoying but at least if you carry on with the routine you're still doing the workout!!
I think Zumba's problem is the routines can be very fast so it doesn't always react fast enough, hope this gets improved. I've also noticed it doesn't always see your feet..

I've played a few mean games of ping pong against a buddy in Kinect Sports 1.. man that works up a sweat if you get a good rally going..

I have Kinect Adventures, Kinect Sports: Season 2, Your Shape FItness Evolved 2012, Dance Central 2 (trial) and I love them all!!!! Great workouts and fun! I also want the Motion Sports Adrenaline, I hear it has a rock wall to climb

Is anyone playing online?

what can you play online!?

I think all of them, I have played Kinect Sports and Kinect Adventures with someone online, but I am not sure about the other two yet.