This is one of the most fun casemods I’ve ever seen. Someone — apparently a Frenchman — was able to cram all the guts of an NES clone into a Super Mario Brothers cartridge shell.
It’s got a slot on the top for actual game cartridges, two NES controller ports, and external power button and LED. It even has standard AV outs so you don’t need to use that pesky cable RF converter.
Nintendo should just start selling stuff like this.