I had a Virtual Boy in working condition, from 1995 - 2009.

It was kind of like a cross between a viewmaster and a Gameboy. The best game for it came bundled with the system: Mario Tennis. If Nintendo were to offer that game as a download for the 3DS in their eShop, I'd certainly download it!

Mario Tennis aside, the overall design was terrible. You had to place it on a table and hunch over to play it, pressing your face against the black mask. If you didn't place it on a high enough table, your back would hurt from playing for more than 10 minutes. Needless to say, the system was kept in its box for most of the time I had it.