The key to faking out the parents is the clammy hands. It's a good non-specific symptom; I'm a big believer in it. A lot of people will tell you that a good phony fever is a dead lock, but, uh... you get a nervous mother, you could wind up in a doctor's office. That's worse than school. You fake a stomach cramp, and when you're bent over, moaning and wailing, you lick your palms. It's a little childish and stupid, but then, so is high school.