Basically I was wondering if there are any inexpensive electronic 'robots', LED displays, etc. that I can plug into my computer via USB (or anything else) that I can program easily using C++.

I just want to start learning how to develop software for basic robots, and program LED displays without building my own and risk damaging my computer ports.

Anything I can buy in Radioshack, Best Buy, Circuit City, all the electronic stores basically? Online stores will work as well.

Just… something I can program to move, display lights, etc.