ViewPure is a great resource for taking away all the comments, ads and other distractions from YouTube video pages. The easiest way to use ViewPure is by using their bookmarklet. From the main page, simply drag the big orange "Purify" button to your Bookmarks Bar (you may have to go to View and choose Always Show Bookmarks Bar if you don't see it.)
(If the animated gif above does not play in your email, click HERE to view)
Once the Purify button is on your toolbar, just go to the YouTube video you want to show, click Purify and the bookmarklet will automatically take you to a simple page with just the YouTube video.
It actually creates a new URL for the video so you can share that with your students in Google Classroom, Blendspace, via QR code, etc. so that they can watch without the typical distractions!