Zune is having a planned outage for their service this coming Monday. The outage could be for as long as 48 hours and is for maintenance and that is about the only details we have. The outage starts at 12:01 a.m. PT on Monday and again could potentially go for about 48 hours.
We can only assume the outage is related somehow to the upcoming Xbox Live outage and they are somehow tied together. Per MajorNelson, the outage for Xbox Live begins at the same time as the Zune outage. Major Nelson goes on to say that this is in preparation for the new Xbox Experience.
Hopefully something interesting comes out of all the down time in the near future.