One of the biggest annoyances of using YouTube as a source of educational videos is those pesky ads they use to drum up their revenue. The are several services, plugins, add-ons and other tricks to get around the adds, but they all require some sort of tinkering from your part. I have used and tested Radbox for about six months now, and I must say this service is a winner. Oh, before I forget, the service is free, and supports about 25 other content providers. In order to use it all you need is an account, their bookmarklet and an Internet connection. Radbox also has an iPad app you can download from iTunes. So go ahead create an account and start showing ad-free video playlists from virtually anywhere you are connected at.