While not strictly broadcasting... I did a bit of playing around New Year's Eve with NAVTEX on 518KHz, just below the AM broadcast band. I downloaded the Frisnit NAVTEX decoder & camped out on the frequency long enough to prove it was working.
Then, I let it run overnight.
Woke up to find messages from eight different sites:
B ZBR Bermuda C NMC San Francisco E NME Charleston, S. Carolina G NMG New Orleans N NMN Chesapeake, Virginia P XLJ895 Thunder Bay, Ontario R NMR San Juan, Puerto Rico U VAR9 Saint John, New Brunswick
NMC was a BIG (and pleasant) surprise. NAVTEX ID C on the East Coast is supposed to be Sept-Iles, Quebec -- but when I read the message text, it was warning of navigation hazards at the Golden Gate and Alcatraz Island!