Workrave

Take a break and relax.Workrave is a free program that helps heal and prevent Repetitive Strain Injuries (RSI).

It monitors your keyboard and mouse usage and uses this information to alert you to frequent micro-breaks, rest breaks and limits you to your daily computer use.

Workrave often reminds you to take a short micro break. Typically, you'll get a micro break every 3 minutes, lasting about 30 seconds. The exact duration and frequency of a microbreak is fully configurable. During the micro break, you can let go of the keyboard and mouse, step away from the screen, and relax a bit.