14th
Sample, Store, Playback
This post about Slow Glass (it takes light a full year to pass all the way through a pane of the fictional stuff) got me thinking about sample, store, and playback—the pattern that first got me really interested in programming.
When I was in high school, I wanted to build a virtual parrot that would listen to the ambient noise in a room, pick out snippets of speech or other unusual sounds, and then play them back at random times.
It was beyond my abilities at the time—I still have no idea how to write classic Mac application—but today I could probably just manage it. Intelligently analyzing the audio is going to be tricky. Playing back the samples in a way that is cute (like a parrot?) is going to be tricky.
But done right it could be a source of amusement. Hmm, it will probably need a moderation queue for new samples, to avoid privacy issues.