The great thing about PC gaming is that many publishers allow the release of modification tools to allow gamers to change bits of the game code. It keeps up interest, allows communities to thrive - and probably gives them an idea of what people would like from sequels. Such a set of tools is coming for PC owners of Skyrim - and they're still on track for this month!
In case you still need the exact wording, Bethesda said of the Creation Kit on its Twitter feed: "We're still looking to have it out this month". Told you so. But don't think this means nothing to you if you don't 'do' modding. The best mods will be made available to download via Steam, so you can sample the best mods and rate them.
Fully voiced (with many, many more voice actors than the original - see what we were just saying about ideas for sequels?) and with many, many hours' worth of story and side quests, it's as-near-as-dammit a full-blown expansion pack. Nay, a full game.
Of course, that game did take some four years to make, so we will probably see the first, full fan-made Skyrim episode in... ooh... 2016? In the mean-time, expect plenty more minor mods like this Randy Savage dragon as well as whatever DLC Bethesda itself has planned.