This Chrome extension makes life a lot easier for downloading videos from Youtube. I make a habit of downloading videos I will use again in lessons because sometimes content does disappear. Not to mention that reliance on an Internet connection during lessons is not always a good idea; we've all seen the 'spinning circle of no-show' as learners sit expectantly staring at a black screen, haven't we? In the past, I've used Keepvid but now there's no need for 3rd-party sites. Just add the extension to your Chrome browser using the link and watch the video below for directions on how to use it.
NB This will only work with Chrome, not Firefox, IE or any other browser so if you don't have it, it might be worth downloading.