Like Odysseus, who voluntarily asked to be tied so that he doesn’t succumb to the call of the Sirens, some people want to voluntarily give up temporary web browsing capability for a user-specified amount of time, so they can focus on work.
Is there any software that does this?
Do you use Windows, a Mac, or what?
I am pretty sure that Linksys routers have this capability and probably other brand too. One would cost about $40 or so.
If you use Firefox as your browser, an extension is available called Leechblock.
I love Leechblock, in a love-hate sort of way. It works splendidly.
My idea was to clone your hard drive, and delete the web browsers from one of them. Boot off the other, and use that for work. With a Mac, it would probably work best of the browsers were on an external, since you can’t usually disconnect the the internal one in a Mac. If the web browsers were on an external drive, you could disconnect it and put it away somewhere.
Linksys certainly has this capability. I am almost sure every router sold today has this capability. It certainly wouldn’t be hard to find such a router.
Just set it up to block internet access during certain times of the day. You can do it on a machine by machine basis, so not everyone has to drop off the net at the same time.
I am reminded of this story:
An alcoholic came to see the Zen Master. He said, “Master, I have a problem. I am addicted to alcohol, and cannot stop drinking. I am constantly drawn to it in every waking hour.” The Master replied, “I see. Yet, freeing yourself from your demon is as easy as opening your hands.” The man was perplexed by this strange comment. “What do you mean by this?” he asked.
“Try to hold a glass with an open palm,” the Master replied.
Of course, this story has little to no practical relevance to someone stuck with a boring task and easy internet access. 
Leechblock is OK, but it’s still too easy to open another browser to use. And on a Windows system it’s pretty much impossible to get rid of IE.
Configuring a router is not an option at the office.
Aren’t there other options? I remember at least one freeare (software) firewall had this capability but I can’t remember which one.