I'll probably leave with my next exams if I finish and have checked enough to make sure I've done everything to the best of my ability. I know I'll finish early with biology and maths.
Yet in the school ones you couldn't leave. I thought about sex, or drew pictures on my exam pad.
If you can't or don't want to leave the exam just yet, you can always try a few things from the website below. Some of the suggestions sound...interesting