I do have a Virtual Boy, and I like it. And honestly, it's not completley out of the question that I do make some kind of music cartrage for it. I'll have to do some reading on what pins are what and where and everything first though... I hope there's some documentation about it... There probably isn't...
Tpam thinks I sould try to create a daw for Virtual Boy
Edit, actually... It looks like it already exists... Kinda anyway. Or, there is an emulator... And a few other cool things here
http://www.planetvb.com/modules/tech/?sec=toolsI might get a flash cartrage and try to make something on that anyway.