What does "FREE" mean? In general, "free" means videos can be used for personal (offline) projects. Usually restrictions apply for businesses and published (online) projects like blogs. Read each web site's "copyright notice" or "user agreement" before using. Viral videos come in a variety of subjects and come in various lengths. "Viral" means "popular."
Download the viral videos on this site with button just below the video player on left side.
Internet Archive: Moving Image Archive
This section of the famous InternetArchive.org offers several video categories to choose from. Once you choose a video, you can download it in MPEG4 or Ogg format using the menu on the left.
Use SpinXpress to search and download from Blip.tv.