Over the weekend, I got the following recommended update to Windows 8:

Intel Corporation driver for Intel® HD Graphics Family (Microsoft Corporation - WDDM 1.2) (Recommended) Windows Update

It started causing flicker during any video playback including backgrounds such as in the Weather app.  If you are having the same problem, there is an easy fix.

Rollback to the Intel Corporation driver for Intel® HD Graphics Family (Microsoft Corporation - WDDM 1.2) to 8/3/2011 v 9.16.10.2472

I used the Driver rollback feature but did not work remove the flicker even after reboot, so, I loaded the driver from the USB drive that was given to us at build. It fixed this issue.

Hope this helps some of the attendees from Build. It was the best conference ever.