In my previous post I shared the idea of using extended display mode to choose what is and isn't displayed on the projector in your classroom. If one of the things that you want to display is a YouTube video, you'll want to make sure that you don't accidentally display the "related" videos that appear on YouTube. You can avoid displaying related videos by using one of the following free tools. None of these tools will bypass your school's filter nor will they let you download videos.
Watchkin is a service that allows you to watch and project YouTube videos without seeing the related sidebar content typically seen on YouTube.com. Watchkin can be used in a few ways. You can enter the direct URL of a video into Watchkin to have the sidebar content removed. You can search for videos through Watchkin and have family-friendly results displayed (if a video appears that is not family-friendly Watchkin has a mechanism for flagging it as inappropriate). Watchkin also offers a browser bookmarklet tool that you can click while on YouTube.com to have the related content disappear from the page.
View Pure is a simple little tool that strips way all of the distractions of related videos, comments, and promoted videos. To use View Pure just copy the link of a video into the "purifier," click purify, and your video will be displayed on a blank white background. You can also install the View Pure bookmarklet to accomplish the same goal.
Quietube is a handy little browser extension that removes all the clutter from YouTube allowing you to view only your selected video. Quietube removes all advertising, sidebar content, comments, and ratings. Installing Quietube requires nothing more than dragging the Quietube button to your toolbard. Then anytime that you're on YouTube click the Quietube button to remove all of the clutter and just watch your selected video. Quietube works for Viddler and Vimeo videos too.
SafeShare.tv makes it possible to view YouTube videos without displaying the related videos and associated comments. To use SafeShare.tv simply copy the url of a YouTube video and paste it into SafeShare.tv. SafeShare also offers browser bookmarklet that eliminates the need to copy and paste links.
Embedding YouTube videos into Google Slides, a blog post, or wiki page will also allow you to show videos without displaying the sidebar content that is typically found on a YouTube page.