I got this advice from someone I greatly respect and it works extremely well if you are tired and just need a little bit of sleep to keep going:
- Sit in a chair at a table.
- Clasp a quarter (other coins will work) in between the thumb and forefinger of your right hand (your left hand will work as well).
- Place the quarter edge onto a plate or saucer (basically on to any surface that will make a sharp noise when the quarter hits it).
- Close your eyes.
- The sound of the quarter falling when your fingers release it will wake you up and you will feel refreshed.