We've seen Star Trek-inspired doors, TouchPad-enhanced microwaves, and Morse code Twitter transliterators made from Arduino microcontrollers, but how about something that can inspire children in emerging nations and give electronic waste a good use? That's what Dhairya Dand's ThinkerToy set of "educational fun interactive toys" are designed to do. There are four prototype models like the Keyano, which repurposes an old PS/2 keyboard into a piano with the help of an Arduino and a small speaker, and the Randomath, which presents kids with math problems on its LED screen and accepts inputs from an unused keyboard as well. The project gets a bit more ambitious with the Storynory audiobook player and TV++, the latter of which takes advantage of old CRT TVs and turns them into educational game consoles controlled by a mouse and keyboard. Dand says each of the toys has a target price of $5, and while he's currently working alone on the project, he's started the openToys community of toy designers and engineers to contribute to make more open source schematics for more ThinkerToys. If you're interested in the project, check the source link below for more information (and a few more photos).