It's an officially Nintendo licensed Mario Kart DS Mario vs Yoshi Race Set, complete with scenery. I guess you can control the speed of the karts with the supplied controller and this thing would probably need a power socket to work.
Anyways, if you don't like that green dinosaur (I'm one of those who don't), there's a Mario vs. Donkey Kong race set too.
Just don't expect blue shells to come with these things. Banana peels are entirely optional on your part :).
Really nice stuff, click here to preorder the Mario vs. Yoshi race set or here to preorder the Mario vs. Donkey Kong race set.