I sometimes use Temptation Blocker (http://sourceforge.net/projects/temptblocker/). It prevents access to certain applications for a specified period of time. I'll block Firefox -- where all my typical news/blog sites are bookmarked -- but leave IE unblocked in case I really need to google something (some sql syntax, for example) work related. I could of course cheat and surf using IE, but that generally causes enough cognitive dissonance that I'm able to resist the temptation.