From Optflux
If you’d rather do without the problem of downloading a certain download youtube videos to download your favorite YouTube video, it's possible to readily online tool. Though there are lots of web-based download platforms for YouTube, GetanyVideo is our current favorite. It’s and also fast and won’t have you clicking through pages which spawn popups or any other intrusive ads.
1: Discover the YouTube video you want to download and copy its URL in the address bar on top of your browser window.
Step 2: Visit the GetanyVideo webpage.
Step 3: Paste it in the bar that reads “Enter the video's link...”
Step 4: Select your chosen video format and click the respective blue “Download” button for the right-hand side.