Thanks to this video I now understand how a yo-yo works but it doesn't mean I'd be any good at it.

The things this guy can do with a yo-yo are pretty amazing, but even more so when you think that the yo-yo is not tied to any part of its string. If you watch this video, they go into the physics of how his tricks work, which is basically a miracle of friction. What some people can do with some things is truly amazing.