Cyber Gadget's Famiclone
The Famicom is the Japanese version of the old-school Nintendo Entertainment System. So imagine my glee at hearing that I can now get a Famicom(NES) adapter for my DS's GBA slot.
It even adds a TV-out port so you can hook up your CRT and it will be just like the good ole days. This adapter does however lessen the portability of the DS, but for the ability to play NES games on the go, I'd say it's a worthy sacrifice.
Now all you have to do, other than buy the Famiclone, is find some good NES games. Then just make sure everything is charged up and you should be good to go for some hardcore gaming while on the plain, train, or in the back of an automobile. No word on price or availability, but you'll probably have to get it through your favorite Japanese importer if you want one.
NES carts now playable on the DS [via ubergizmo]