I've got a handful of these in a drawer at home. I remember rushing to RadioShack to get one as a kid with such excitement. Followed by disappointment that there wasn't much to do with it. I picked the other ones up at the Goodwill soon after.

My computer at the time if I recall had the big DIN connector instead of PS2 so I had to get a DIN->PS2 and a PS2->DIN connector to put this thing inline with my keyboard.