Windows 7: Can I block sites between certain times?

Hello

I have just got a new laptop with Windows 7 and IE8 to write up my thesis. Trouble is, I know I am easily distracted by certain websites and I want to remove the temptation to visit them while I should be working. I can't completely disable the internet since I need to be able to search for work related things. Is there a way I can block my distraction sites during the day but allow access after a certain time in the evening? I tried to look into the parental controls, but since I am the only user and my account therefore has admin rights, I wasn't able to (unless I'm missing something?)

Thanks for any advice.

If you want parental controls, set up another account, standard user, and apply controls to that.

If you're using Firefox, get the BlockSite Addon. You can have your mom or whatever set a password and block your sites, and when you want to get back on them, just have her put in the password

Learn self control? I think there is medication that you can take.