Don’t fall asleep.

If I could offer you on piece of advice on relieving boredom in an examination, not falling asleep would be it. The benefits of not falling asleep have been discussed by many students, whereas the rest of my advice has no basis other than my own meandering experience.
Sincerest apologies to Mary Scmich.
Hum your favourite song.
Rock back and forth, casting darting, suspicious glances at everyone who looks your way.
Try to use telekinesis to make the clock move faster.
Watch people.
Draw something.
Erase it.
Draw something else.
Spend time planning ridiculous blog entries like this one.
Sketch a cartoon.
Play doll house with your pens and pencils.
Write a story.
Count the number of tiles in the ceiling.
Leave funny notes on your exam paper for the invigilators to laugh at.
Measure your pulse rate.

And lastly, check your answers over exactly one minute before the end of the exam. This never fails to induce a last minute panic that you can do almost nothing about.

Pax.