Update: Microsoft has just posted an official explanation for the problem--it's related to a clock driver that doesn't handle leap years properly. So apparently, the Zune 30 is date-aware. The fix: wait for January 1, let your battery run down, charge it up again, and turn it on. I'd suggest giving that a try before trying to pry the case open to unplug and replug the battery.
Reports are coming in from all over the Internet that 30GB Zunes--the original model, which Microsoft shipped in 2006 and 2007--are all freezing up at once.
I have one of these original Zunes, and indeed it's stuck. (See the picture, which was taken with my, ahem, iPhone...no freezing there.)
A bit of background: Microsoft actually didn't build or design these first-generation Zunes--Toshiba did. From what I've read, only the 30GB models that have been updated with the Zune 3.0 software (released in November 2008) are freezing. This points to some sort of problem with the firmware on whatever processor was used in the original Zune, and its interaction with the Zune 3.0 software.
Could this be a Y2K-type bug?The Zune uses Windows Media DRM 10 for Portable Devices to support the Zune Pass subscription service. That DRM system includes an on-board clock to ensure that subscription content can "expire" if users stop paying their fees. (Basically, if you don't sync the device every so often to let it confirm that you've still got an active subscription, it disables the subscription content. The exact time period is set by the manufacturer, but I don't know how long the Zune lets you go without a resync--or even if it uses this feature.)
But I doubt the clock actually knows today's December 31--rather, it probably counts a total number of seconds since some particular zero date near the device's creation. So that clock might have reached a number that's too large for the field created to hold it, but the fact that it happened on the last day of 2008 is probably an unfortunate coincidence. It's almost funny, except for the fact that I've got 25GB of music locked up on this brick.
I'm expecting Microsoft to issue some sort of firmware update to fix the problem, but the timing--a week before CES--couldn't have been much worse. If Microsoft so much as mentions Zune next week, look for every wag in the audience to Twitter about the pink-and-black screen of death.