Note: Gifsoup, as it turns out, is a violation of YouTube's terms of service, which state that user-submitted videos cannot be downloaded unless the author has allowed it and the download is taking place on YouTube.com, and not via its API.
In my book, animated GIFs are one step above glitter graphics in terms of junk trends of the Internet, but I'm a big fan of any tool that makes creating them easy and fun. Gifsoup is no exception--you just point it towards any YouTube video and it turns it into an animated GIF.
To do this, it first downloads the clip to its servers, and then gives you simple controls to choose when you want it to begin and end. When you've picked out that perfect 10-second (or less) section of the video, you just hit a single button to finish the job. The GIFs are then hosted, and ready to be embedded elsewhere; you're also able to save it to your hard drive in one of three sizes. Either way, it retains a small Gifsoup watermark that sits in the bottom right-hand corner of the image.
Below are two I made in less than a minute using Gifsoup's tools.
See also: Gickr does software-free animated GIF creation (which uses multiple image files instead of video)