I know folks who consume food to relieve stress. When I was at MIT, I would do the same with international news until discovering http://selfcontrolapp.com/, which was the reason I switched from Linux to OS X.
EDIT: I couldn't help myself :/ Turns out that it also adds some ipfw rules: http://www.joshuakehn.com/2010/10/25/Defeating-SelfControl.h...
Why did I start this thread?
I haven't done too much research but I imagine the best option is a filter that runs on the router and locks itself down for a time period.
[1] https://chrome.google.com/webstore/detail/morphine/fbnpehpbo...