Hot Dots. Kind of out there, even for The Ferret, but kinda cool too. In fact, forget the kids, I reckon that this is a geek funfest waiting for some clever hacking. $12.04.
Make your own games and activities on any surface with this set of 300 “cold” (incorrect) and 150 “hot” (correct) self-adhesive dots and the Hot Dots Power Pen…The Power Pen responds with lights and any of four positive reward sounds or a “BOING” for an incorrect answer.’