This is a little AppleScript application that downloads MP4's of YouTube videos using just the URL.

1. Use Homebrew to install youtube-dl (like so: brew install youtube-dl).
2. Copy yt.sh to /usr/local/bin. (Or wherever you'd like that's in your path.)
3. Edit the hard-coded video download path to point at where you want these videos to go. (I pointed mine at /Users/kevin/Downloads.)
4. Make sure you chmod +X yt.sh.
5. That's all! Run burninator.scpt and you're good to go.
6. Use AppleScript Editor on your Mac to save burninator.scpt as an Application, if you want.

Yes, hardcoding the download path is a hack. No, I don't plan on fixing it, because having the video files show up in ~/Downloads seems to me like the correct behavior. Feel free to fix it, though, if you want.

TJ Luoma came up with the guts of yt.sh. The whole thing wouldn't work without youtube-dl. And you should download a Trogdor png for the AppleScript app icon.

Public domain. Have fun.