Application that prevents you from accessing the internet for a pre-determined # of hours?

I JUST SAW THIS YESTERDAY AND NOW I CAN'T FIND IT.

There's a downloadable program (for Mac, or crossplatform) that lets you tell it a particular number of hours you want the internet to be inaccessible from your computer. I need this application. I have got to get a ton of stuff done today, and I have to be on the computer, but I really need to be CERTAIN I don't log on and goof around.

Anyone know what I'm talking about?

The problem is that I'm sick as a dog, but I have got to do these things, and it's so much easier to dick around on the internet than to focus on work when you're ill. (Let alone when you're well.)

ETA: I need to block everything--mail, chat, etc., not just web access. And I can't unplug the router because shrift uses it, as well as our next-door neighbor. Even if I could, I'm sure that I'd plug it back in after an hour or so for "one thing," and then... yeah.

EATA: anoel comes through! This is the program I saw yesterday!

"Freedom is a simple productivity application that locks you away from the internet on Mac or Windows computers for up to eight hours at a time."

Used by Dave Eggers, Nora Ephron, and Peter Sagal! Featured in the NY Times! :D

*downloads*

*will see you all in four hours*