Interesting. The graphics don't look too hot, but I'd trade graphics for smooth gameplay and the inclusion of ToyBox mode any day.
It also looks like they aren't just copying their brilliant Cars 2: The Videogame but rather are making something completely different. I heard that it occurs after Cars 2, and if so, I wonder what you'll be doing in the game. I would imagine that racing is involved somewhere.
I also like the fact that these in game playsets aren't just video games of the films, they are a separate story from the films that exist in the same franchise. Makes it much more exciting when you don't know the story.
Edit: Just found a link that talks about this reveal. http://www.videogamer.com/xbox360/disney_infinity/news/disney_infinity_cars_play_set_revealed.html