Wickeycolumbus and ppcasm figured out how to homebrew on a Mattel HyperScan ( more info see: http://en.wikipedia.org/wiki/Hyperscan ).

Release notes:

Many people on this forum hate the mattel HyperScan, and thought homebrew would not be possible on it. For the past few months, a guy named ‘ppcasm’ and I have been figuring out how the thing works, and released a few demos here an there. I am not sure if anyone here is interested, but here is a scrolling color demo I just made for it. Written 100% in SPG290 Assembly language. In order to run it, you must have a real HyperScan (no emulator exists yet), and a CD-R. All you have to do is burn the HYPER.EXE file to the CD-R and put in into an un-modded HyperScan, wait about a minute, and the screen pops up with fabulous colors :)

http://www.atariage.com/forums/index.php?showtopic=142478