Since there were some significant changes in Sitecore's RTE when they upgraded to Telerik's new libraries from Sitecore 6.3 to 6.4. I'd written previously about
adding buttons to the RTE
before and was lookin for a good reason to write a supplemental article. Thankfully the new editor actually simplifies a bit of what you'll need to do from the earlier version of Sitecore.
I was recently asked by a content editor how to insert a YouTube video on a page in Sitecore and after thinking about the best approach to respond with my options were to tell the user to change to HTML mode in the Rich Text E