Today is a bad day to be a Zune user, it seems. There are numerous reports coming in from all over about a widespread failure of Zune 30GB models locking up during boot with no ability to turn them off or reset the devices. The problems have appeared in mass quantities on the Zune forums as well as being reported by users at other sites. The problem was recognized by Microsoft hours later with a vague "we are working on it" response.
An unofficial fix has been discovered and requires some minor tinkering. It'll likely void your warranty, but if you have a sense of adventure and a dead Zune, the fix is reported to work without issue.
Then just an hour ago or so, we learned that a software glitch came into effect with the leap year clock. Microsoft's response then:
Q: What is Zune doing to fix this issue?
The issue should resolve itself.
Indeed. By midnight your Zune should be back to normal, at least until the next leap year in 2012 or when Microsoft issues a patch fixing the bug.