There is a hint, which will allow you to play Youtube videos even if it is blocked at your workplace. All you need is a Youtube link and gmail.com is available open chat with anyone from your contacts and paste youtube link. For full screen click Pop-out and resize window. Bingo, what a surprise — video just works fine.
Some of you may tell that you knew about it, but for example at my work youtube.com is blocked and my colleague was always using sites like youddl.com to download videos from youtube.com, when i suggested him this easy solution. 🙂