The ZuneInsider site states that Zune 30’s all stopped working today because of a leap year issue (2008 has 366 days), and that the Zune software will correct itself on January 1st, 2009. So, just let your Zune 30’s battery drain and then sync/charge it after noon GMT. This is only a problem with the Zune 30’s, since it is affecting a specific component only present in that device. The 2nd generation Zunes (Zune 4/8/16/80/120) are not affected.
Now, noon GMT (Greenwich Mean Time) should be the following for those in the US:
EST: 7 am
CST: 6 am
MST: 5 am
PST: 4 am
AKST: 3 am
HST: 2 am
Man, that was a close call for Microsoft. I guess the next time this could happen is in 2012, so mark your calendars! 😦
UPDATE: It looks like the Zune 30s are starting to wake up today, on January 1st. Lots of owners reporting on the various Zune forums that their devices are syncing and coming back to life again.