It is actually made by K'Nex, a construction toy maker similar to Lego's blocks.
The idea is that the kids can make their own track sets and run their own Mario Kart races.
|K'NEX Mario Kart Wii Track Toy's R Us|
(I grew up with it, too. First generation Mario player.)
However, I can just see smaller kids wrecking this track sets and the parents have to fix it.
We have experiences with other sets like Thomas the Tank Engine.