Have a look at this miniTamTam demo video.
I was amazed by the number of things kids can do with this application. The UI is so much intuitive that they can figure out most of the stuff by themselves. But that's not all about it. The best thing is, one can actually make some serious music using this.
When I see these typical toy laptops in market, I feel sad. They don't offer much beyond couple of prerecorded melodies and some cheap learn A-B-C doodles. So once kids are beyond learn A-B-C phase, these toys are no more fun for them. And for such things you have to pay atleast half of what OLPC costs.
I hope they come up with something as bright and as fun as OLPC for all the kids (or OLPC becomes easily available for buying). I would love to buy this for myself.
PS- TamTam is written in Python using pyGTK as the GUI library. It uses Csound as it’s sound engine. I have started admiring Python all the more now.