Over the decades, there were plenty of kooky Game Boy games released in both Japan and the West. Plenty of strange accessories, too, from cameras to printers to blood glucose monitors. But 2001's Mario Family was especially kooky.
Why? Because it was a cartridge designed not to be played, but to be plugged into a sewing machine. So the machine could spit out cute little stitchings of Nintendo characters. How...quaint.
Mario Family was a Game Boy colour title designed to work exclusively with the Jaguar JN-100, a $US600 sewing machine released a year earlier, in 2000. Jaguar, formerly known as Maruzen Mishin Company (and first opened in 1949), is no niche, hobbyist firm; it's Japan's biggest sewing machine manufacturer, so this was a genuine offer aimed at mainstream customers, not something you'd find in the back alleys of a gaming show.
It worked like this: the JN-100 shipped with a special link cable allowing a Game Boy colour to be attached to the sewing machine. Users would couple their handheld to the JN-100, insert the cartridge and then, by "playing" it, could access dozens of Nintendo designs which the sewing machine would then replicate on material.
The video to the left shows the variety of designs available, which users could further customise by altering the colour of each component (changing Mario's overall colours, for example). Up to three of the template designs could be placed next to each other to create little stitched dioramas.
And if you didn't like the included designs? You could use primitive editing tools on the cartridge to create your own.
The JN-100 was released in international markets as the Singer IZEK (in case you've ever seen one and you don't live in Japan), and was followed a few years later by the JN-2000, an improved model which, with the use of an external embroidery attachment (as seen in the top image), could get the work done faster than the JN-100.
All models were, of course, incredibly niche products. I've only ever seen one in the flesh once (and it wasn't working at the time), and as you could probably guess by the lack of follow-up products boasting DS and 3DS compatibility, it was an idea that never took off.
Oh, and sewing enthusiasts (I know you're out there!) should also note the JN-100 was the first machine featuring computerised design inputs to be available at a mass-market price. If you want to pick one up, it was discontinued in 2006, but eBay or other similar markets should be selling one from time to time (Mario Family, on the other hand, might be a little harder to find).