Words we shouldn't use

I'm having one of those moments when I just want to shout "SHUT UP!" at the top of my lungs because (only God knows why) my children that are five years apart need to fight with each other like they're about to jump into a boxing ring. "Those be fightin' words" comes to mind when I look into my daughters eyes as she's glaring into my son's. Pure rage.
How we handle ourselves in these situations is beyond me. Don't get me wrong, I've had to break up a fight and run for my room... just to get a grip on my own temper! Is it just me, or do kids have this sense of when you're about to crack and then slam down the hammer with another bout of screaming?
I have seen so many different forms of parenting. One of my sisters is a teacher, for heaven's sake! But I don't believe in time out, because no child is ever going to sit there and think about what they did wrong. Time out is for parents that are about to blow their top and the safest place for said child is sitting down somewhere quietly... away from the twitching hand. I'll admit it. I'm a yeller. That's when they know they can still have a little room to get away with whatever they're doing. The minute I stop yelling, they know they've pushed me too far.

I am all for the revoking of privileges and electronics (or whatever is most important to them at the time), so I am currently threatening their summer swimming time. I know what you're thinking. What single mom has time for that? Considering the fact that most of my work is done at home in my own timing, my kids are with me ALL summer. No dads on the weekends, no friends that live nearby to dump them on, no summer camps (cause those suckers cost some serious $), and in my situation... Nana isn't happening. I get to keep my unhappy little campers right here at home! There was one rule that did stick as school let out for the year, though. "If you say you're bored, I'll give you something to do." Twelve days in, and I have the house somewhat cleaner than it normally is, my electric bill will be lower (thank you paperback books), and I am no longer in charge of making lunches. Go me!
So, I'm sitting here gritting my teeth so I don't yell "SHUT UP" and thinking of other words that I'd prefer to say but won't. Here's my question for you:

• How do you personally control your temper when your child is out of control?