http://en.wikipedia.org/wiki/Radio_Data_SystemI've been in cars that have this, and it's quite nifty. Your local radio stations send out small amounts of data that can include information on the songs that are playing, and current clock times for synchronization purposes. It also sends out each station's call letters.
Is there anyway RDS detection could be implemented into devices that have FM radio receivers? It would be cool to see what song title/artist is playing when using the radio.
Also, maybe you could use RDS as a way to auto-sync devices that have real-time clocks to the correct time.