Is there a way to block a specific website using Firefox?

[arabian]

I know there has to be. Can anyone link me to where I'd need to go to do so, or give me a quick run-down?

I really need to block a website for my blood pressure. I'm seriously not kidding.

One guess as to the website. (Revealed in comments.)

Comments

[sinca.livejournal.com]

Wow, ridiculous! I have had someone else on my friends list banned for something stupid in the AI forums. I hate that place and I never go there for anything important anymore.

[arabian.livejournal.com]

I've FINALLY learned my lesson.

Still, it's frustrating because I like the concept and the style of posting so much. I commented in eolivet's journal that HiddenEloise and I are playing with the idea of making an alternative to TWoP because the posters (for the most part) are great, the idea of really letting go about shows and having fun with it, along with deep conversation is a fabulous idea. It's just that on TWoP, the people who run that place are HORRIBLE, POWER-HUNGRY NIMRODS!