Sharp released a number of interesting Famicom-related systems. One of the more widely known and popular is the Twin Famicom, which took the Famicom and Disk System and combined them into one console. Sharp also developed the Famicom Titler, which is the only Famicom console with s-video and strangely allows for things like subtitles to be added to your home videos (yeah, the latter has nothing to do with Famicom).

Sharp only ever released one game, and it wasn't anything unique, except for the fact that it contained both Donkey Kong Jr. and Donkey Kong Jr. Math. This 2 in 1 cartridge was packaged with Sharp's C1 television. The TV was extra special, because it came with a built in Famicom and is the most difficult of all the non-pirate consoles to find.

Other than being two popular Nintendo games on one cartridge, and the only licensed multicart ever released (I think), the cartridge is nothing special. The games are what you'd expect but the "menu" screen is unique, having "Sharp Corporation" listed in the copyright.

Despite the fact that the C1 is so rare and that this cartridge was never sold separately from the C1, this cartridge isn't all that rare. Sharp's Donkey Kong 2 in 1 sells for less than $30 in Japan. But since you'll hardly ever see it on eBay, it would likely sell for much more there.