Ok for all of you that just can't wait until midnight to use your Zune here is a quick fix that will allow it to work in the meantime.
First you have to open the Zune, if you don't know how here is a video that shows you how http://www.se7ensins.com/forums/zune-support/91483-open-your-zune.html
You don't have to do all the steps in the video, once the cover is open just follow what I've written below.
after you open it disconnect the ribbon cable on the bottom right side of the hard drive, Thats the cable that runs over the top of the drive to the battery. Let it sit for a couple of minutes then reconnect it. If all goes well the Zune should reboot and allow you to use it as normal.
The catch to this is you can't set the clock to the correct time, if you do it will freeze up on you again, I've tried this on multiple Zune's and the only one that I have an issue with is the one I set to the correct time.
Do this at your own risk. I do not take responsiblity for anybody that damages their Zune by following this procedure.