Okay, so it's not THAT "One Ring", but I like to think of it as the One Ring of working in the round. Especially if you get frustrated at the hole left in the middle of your hat/motif/afghan/you name it with other methods. I recently tried this when making the button for the font of my Poké Ball hat, and I love it!
You can find great photo and video tutorials all over the web, but I think these two from PlanetJune are excellent. She's posted a right-handed tutorial, and a left-handed version as well!
Here's a little peek at her tutorial:
If you love in-the-round projects, but hate that little hole that's left in the center, you should definitely learn and use this technique!