How do I make it stop?

How can I control getting interrupted 9million-bazillion times a day?
I was working through a nasty problem today, one that required a lot of concentration.
I got interrupted 7 times in the course of working on this problem. I finally 'sort of' got things working the way I wanted..then more interruptions and some really lame-ass questions...the kind of questions that if someone would just think for a second, they would come up with the answer themselves, but I guess it's easier to just ask me. Anyway, now I'm back to my original problem, and since my brain has been run through the gamut, I can't remember what track I was on to get this fixed, so I'm screwed. If I leave it now until Monday I'll never remember half of what I went through today to get it partially fixed so I guess I'm here for the duration...yea Friday night!
So...do I need to just start screaming at people if they come and bother me? leave the office if I'm working on something gnarly so no one can find me?
Rant over...back to stinking dumb ass can't be easily figured out problem.