RSI Warrior is a fantastic freeware ergonomics software package which helps computer users prevent and recover from computer-related Repetitive Strain Injuries. It achieves this by providing the user:

Rest break reminders that are timed based on how hard you actually work at the computer, and designed to be as unintrusive as possible.

Over 20 professionally designed stretches shown during rest breaks to guide you through your stretching break. These stretches are presented as 3D animations.

Microbreaks which give you time to briefly relax, regain awareness of your posture and work patterns, and maintain awareness of how your body feels.

Tracking & reporting of key work statistics to help you understand how you use your computer.

Automatic clicking to eliminate the strain associated with mouse clicking. This works by automatically dispatching a click whenever you stop moving the mouse. This works great if your RSI is induced by over-clicking.