Here’s some fun. (For a sufficiently nerdy definition of “fun”.)
Launch Safari 4 or Chrome 4.
Drag Videotate to the bookmarks bar.
Find your favorite YouTube video. Or maybe your least favorite. Here’s one of my favorites: Walk Don’t Run. Here’s another that’s not necessarily a favorite, but it seems like a fairly appropriate choice.
Note: not all videos are available via HTML5, even when you’re opted in. If you get a Flash video, the bookmarklet won’t work.
Once the video has started playing, activate the “Videotate” bookmarklet.