Skyrim recently reached an amazing achievement in the steam workshop, there are now over 10,000 mods available for download. This huge number of mods is made possible by The Creation Kit, which allows anyone to be able to make mods for Skyrim. The 10,000th mod uploaded in the workshop is a sword mod from Joe Powell and is his first mod ever. Steam did an interview with and can be found here.
One of the great things about The Creation Kit is that it allows you to do nearly anything, and if you have a lot of modding knowledge you can create amazing things within the Skyrim universe. If you are interested in trying to make your own mods there is a Creation Kit wiki available that will guide you through the modding precess.