Gaming
Tomvdcr, a gameboy modder, had the idea after noticing the fourth generation Pokédex was designed in the same vein as a Nintendo DS Lite.
The process entailed gutting the toy Pokédex, inserting the DS hardware, and then trimming the motherboard so that everything could fit nicely.
According to the man behind the machine, the Pokédex DS Lite is his best handheld mod thus far. Maybe Nintendo will look into a possible collaboration for the upcoming remastered Diamond and Pearl versions?
Aside from the Pokédex DS Lite, Tomvdcr has made a number of different handheld mods... namely putting Gameboy advance or DS hardware into Gameboy colors.