Many years ago, I had this idea for a ring that combined sound detection, storage, wireless technology, and some bundled smarts. The idea is that you could key it to a certain triggering sound, which would then run a script on the computer in the closest proximity. Depending on whether or not the ring had anything stored in it it, it would either suck in or spit out the computer's available data.

Basically, it was a way to snap your fingers at one computer monitor and snap again at another to transfer a screenshot between them.