There are so many hot videos on YouTube, just take some free video downloading sites like keepvid: http://www.videoconv...e-keepvid.html to get them download.
You can convert the DAV files to AVI format if you want to play them on other devices. Also, if you just want to play these files, KM player can help you as it can play some DAV filed directly: http://www.kmplayer.com/