source

1. Find a video on YouTube—like this one—and copy the URL from the address bar.
2. In VLC, head to Media > Open Network Stream.
3. Paste the YouTube link in the box and click Play.
4. Under Tools, click Codec Information.
5. In the box that says Location, right-click the block of text and click Select All. Copy this text to your clipboard.
6. Go back to your browser and paste the link in the address bar. This will open the source file directly on YouTube's servers.
7. Right-click the video as it plays and select Save Video As.

You can also record clips from YouTube videos as they're streaming in VLC by pressing the red Record button in the player itself. This isn't as direct of a rip, but it's handy if you need to grab a particular clip out of a long video.