I love this extension for Chrome: clea.nr. It cleans up Youtube entirely – no related videos, no comments, just the video I want to show my class.
Once it’s installed, youtube.com looks like this:
Those recommended videos in the sidebar can be terribly distracting. This makes a Youtube video feel so much more appropriate for classroom use. Especially when watching something that leads Youtube to make terrible suggestions, like videos of what a “jerkline skinner” does to better understand Of Mice and Men.