I was really surprised to see WiFi adapters for the Gameboy Advance being offered for about $15 apiece.
I did some googling, but could find any info on how it's interfaced to the GBA, or whether it's possible to replicate that interface with something else (like, say, an Ardino ;)).
Anybody got any info on this? Even if it's range- and/or bandwidth-limited, a WiFi connection for less than the price of an Xbee (much less an Ethernet shield) sounds extremely cool.
But, while I was googling to re-find it, I came across a slashdot posting suggesting it's not really WiFi, and may be Bluetotth (or even something else using the 2.4GHz band).
Still, even if it's not WiFi, it could be a cheap wireless link if the interface isn't too weird.