"ViewPure is a service that allows you to watch and project YouTube videos without seeing the related sidebar content typically seen on YouTube.com. ViewPure offers a free browser bookmarklet that you can use to clear the sidebar content while viewing a video on YouTube."
Via EDTECH@UTRGV
If you have ever had embarrassing content pop up on the side while showing a YouTube video in class, check this out. It allows you to watch content without all the other "stuff" that appears on the screen.