Zamzar - Free online file conversion
Asked to help with a project to put a few Youtube clips together in iMovie. Just a short intro before a meeting. The amazing ability for us to find so many online resources is dizzying. I punched in a search and came up with Zamzar. Fed it two links to Youtube and the site pulled, converted and emailed me a download for them. Loaded them right into iMovie. Not extremely high quality, but for a bit of fun, it was very simple. Just be prepared for a few hours delay until you get the download link via email.