And for some reason, the conspiracy theorists are out in force. But there’s nothing to it, really: Microsoft says it is just updating its infrastructure to support the November launch of the new Xbox Experience. (Zune and Xbox run on the same back-end.)

Here’s the Zune perspective (via email):

The Zune service will be down for scheduled maintenance on Monday, September 29, 2008 from 12:01am Pacific Time, for up to 48 hours. During the downtime, Zune Social, the forums on Zune.net, and all of Zune Marketplace will be offline.
We apologize for any inconvenience this might cause you.

Please check back soon. We look forward to sharing our picks, plays, and recommendations with you in the Zune Social and in Zune Marketplace shortly!

Sincerely,
Your Friends at Zune

And from the Xbox guys:

Xbox Live Service Maintenance

On Monday, 9/29/2008 from 12:01 AM PST for up to 24 hours, Xbox Live will be offline for maintenance. As a result, Xbox LIVE and the ‘My Xbox’ section of Xbox.com will be unavailable, and the Xbox forums will be in read only mode (you won’t be able to post.) The remainder of Xbox.com will be available with limited interruptions.

This service maintenance is in preparation for the new Xbox experience which will be available later this fall.

Let me reiterate: When the service returns, you will not have any new features and you will not have the new Xbox experience update. That will happen later this Fall.

Nothing to see here, in other words.