Tim Schuerewegen made WiFiMe: a "wi-fi" work around for "PassMe" - the only device capable of permitting us to run our own homebrew code on the Nintendo DS.
This miraculous event just happens to coincide with... me finishing my month-long project to create my own PassMe from Natrium42's design. This hideous monster was the first project of this level I had ever undertaken and it required etching custom PCB boards as well as an insane amount of soldering and seating those infinitesimal PCI pins!
I'm not slapping my face with the maddening irony of it all - I welcome it. When my PassMe breaks I've got some kind of backup.Check out this photogallery of the apparatus and the building of it. I made it entirely from photo's on Natrium42's site. Most of the parts were pulled from a dead PC (including the PCI pins) and the cost of the actual components was well under $20.
You have no possible reason to make one of your own because of WiFiMe... but even a monkey can do it if sufficiently induced. Apparently. Be sure to check out the awesome green/black stains the copper-dissolving etchant left around my drain!