1. Rest your left elbow on the work desk and place your forehead against the fist. At the same time, hold the mouse with your right hand. This is so cool!
2. A variant of the first technique is to get close to your monitor. Rest both elbows on the work desk, placing your forehead against both fists. It's just like you're thinking too deep about the task at hand.
3. Wear opaque shades, cross your arms, lean back and may you have sweet dreams!
Just beware in employing these strategies. The screen might have turned black already.