Apple have just rolled out an update to their second- and third-generation Apple TVs, with the update reportedly fixing some bugs in a previous version, and, well, not much else. If you want to update your Apple TV to 5.0.1 (9B206f), all you have to do is turn on and initiate the software update on your own.
Normally this would happen automatically, but if it doesn't, that's how you can do it. Alternatively, you can download the updates directly from Apple:
If you're using an Apple TV and update it, be sure to come back and let us know if you've found any other changes, or had any issues!