So, while playing about with Blend, I ended up creating a Pomodoro timer as a Visual Studio 2013 Extension.  I've published it now (it's free), so if anyone wants to give it a whirl feel free to grab a copy (either direct from the web, or from within Visual Studio by searching for 'pomodoro') and give me constructive feedback, it would be welcome.

It's a deliberately simple affair -- click to start, get alerted when it's time to rest or restart, click to stop. 

If you like it, please review and rate it in the gallery.