One of my more notable hacks.
I managed to build a kiosk that would upload Podcasts to visitor's iPod(tm) based device. I wrote the app in Tcl and Applescript. I've been asked not to say any more about it from a company in Australia who is using a similar process for a commercial venture. ;-) All I can say is the process used software built into the Mac that allowed our software to interact with the iPod and not put the user in any danger of voiding his or her warranty.
Where my project ended and the commercial venture took off was in finding a way to deal with folks whose iPod was programmed only to sync with their home computer. (Which in my analysis was actually most of the ones the Kiosk encountered.)
The kiosk was completely buttonless. Users would simply connect the iPod dock cable, and the rest was completely automatic. There were some glitches, naturally. But this was a side project in the middle of a giant exhibition.