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