Have you ever been presenting in a room full of people and suddenly your presentation disappeared because your computer went to sleep? Before we started using Caffeine, this happened to us all the time.
Caffeine is this nifty little application from Lighthead Software that keeps your computer screen from going to sleep.
The application puts a little cup of coffee in your Menu Bar. When you want to keep your screen from going to sleep, just click on the cup of coffee and you fill it up.