I yell that on the first drop of Corkscrew and Gemini every once and a while.
I like what's yelled on the first drop of Millennium Force by about all the riders. :)
If you're in the middle, you can hear the people a few seats in front of you say "Oh ****!", then the next seat, then the next seat, etc.
My friend is scared of heights, and when we were going up the lift, he just stared out towards Lake Erie and kept repeating, "We're gonna die, we're gonna die." over and over. I thought it was funny, so when we started the "launch" I yelled at the top of my lungs, "We're all gonna DIE!!!!"
I yell as loud as I can on Millennium Force, and I usually pay for it. The first day I rode it, after the first 3 rides, I barely had a voice left, and after the 4th, I couldn't talk.
Then the next time I went to CP, my voice was hoarse after the first ride.