I'm in grad school and one of the main things that distracts me from my dissertation is the internet. The trouble is, I also need the internet to do my work (e-mail, research, etc.). I want to get more hardcore about limiting my time at specific internet sites, while still allowing access to the sites I need for my work. Is there any software like those parental control programs, but that would allow me to restrict my own access to entertainment sites for a specified time each day. For example, it might let me view my favorite videogame sites for 60 minutes per day, but then it blocks those sites for the rest of the day once the 60 minutes has been reached. The problem with most programs is they either block certain sites all the time, or if you can set a time limit, it only allows a time limit for all internet usage.
Freeware would be preferred naturally, but I need to get a lot of work done quickly and I need to be rigid with myself about how I spend my time, so I'd be willing to pay for something at this point too. Any advice on a program for me?

With 95% of them being malware ;)

The best why I found when writing my papers and doing all my research (and that I still plan on doing for future classes) is when you want to study, pack up your shit and go to the library.
You'll find that actually being in that environment will keep you from being distracted, while giving you access to tons of reference materials other than internet (My teachers are anal about internet sources, so I use books almost exclusively).

I'm looking for a job, so if he pays me well enough I am willing to do the punching.
Going on campus is a good tactic, I would seldom look at random shit on campus. I mean who wants to look at cat porn in the library where everyone else can see you?

that'd work too. if you don't mind switching between browsers. And as long as you don't add too much stuff to chrome, and can hide the tab bar, etc..
Also, if you don't REALLY need the internet, email, etc.. and have a laptop... take it to the library (as someone said) or the coffee shop.

lol . . .I agree . . . I think Ois has the best solutions.

I tried something similar when I was under pressure to finish my master's thesis. It didn't really work. The actual time I spent procastinating went down, but only slightly, and I soon found I was simply redirecting to other non-constructive activities instead of surfing my favourite gaming websites, or whatever. Heck, at one point I started playing multiplayer Quake again for the first time in 2-3 years, this was less than a month from my final deadline.
Back when I was just reading for exams, I could just visit the library, or even better, designated reading areas where laptops were not accepted, and the problem would go away. However, on a thesis this is virtually impossible.
My experience was that it's not effective to punish yourself for "wasting time", instead reward yourself for spending your time constructively. Also, set yourself small, managable goals. I started breaking every day down into about 20-30 small tasks, and I had a whole reward system set up for various degrees of completion. It worked wonders, and I ended up doing at least 30% of the total thesis work in the last 10% of the allotted period. I was exhausted afterwards, but damn did it feel good too.

Thanks for the advice all. I decided that rather than risk exposing myself to some nasty malware, I will just edit my hosts file and ban myself. It is just easier that way. I'll probably be back to my heavy posting self in several weeks after I get through this hurdle.