Bethesda has opened up testing of features coming to the next update of Skyrim to those who opt in to the beta on Steam. Version 1.9 will add a new difficulty setting and allow players to tag any of their rating 100 skills as "Legendary," resetting them back to 15, returning perks and allowing the skill to affect leveling again. So, now you can play Skyrim forever and always feel like you're making progress.
There's also a whole bunch of bug fixes, far too numerous to list here. You can check those out on Bethesda's blog.
The update is expected to release publicly later this month.
Now on Steam: Skyrim 1.9 Beta Update [BethBlog]