So Andy may have something better but I downloaded this and it’s free http://www.teamviz.com/
It does not lock out Facebook but it has made me much more aware of my time as I work and I can check FB on my breaks or actually schedule 25 minutes for FB. The alarm is annoying so you know it’s time to get off. It also has been interesting when you plan how long to work on something and then some things take less than you though and some take more. I was saying to Bradley, I wish I had kept track of my actual time from the beginning, this would have been a way to make that easier.