updated 02:24 pm EDT, Thu August 29, 2013
Issue unreported on Apple's system status page
A number of users are reporting that access to TV shows has vanished on the Apple TV and in the Mac and Windows versions of iTunes. On the Apple TV, the app for TV shows has disappeared; in iTunes, trying to click on the "TV Shows" tab in the iTunes Store may boot users back to the storefront's homepage. Apple's system status page shows no sign of the problem.
The issue is presumably a glitch in Apple's infrastructure. Apple has also been making a constant stream of updates to the Apple TV however, which could require temporary downtime.