These are great toys. If you ever see one at a yard sale you should not hesitate to buy it ASAP. Not only is it a feat of engineering magic, it’s also hackable. The ICybie site is full of links to info on how to modify and program new cartridges to create personalities, make an RS-232 connection to your PC, and even write your own code in for it.
The grand bin of links and hacks!
[AiboHack] ICybiePet’s ICybie Site
Official site Silverlit