Prevent RSI by using workrave

Workrave is a program that assists in the recovery and prevention of Repetitive Strain Injury (RSI). The program frequently alerts you to take micro-pauses, rest breaks and restricts you to your daily limit. The program runs on GNU/Linux and Microsoft Windows.

It have feature to sync with other computer in network. So all computer would have same timing for alert. Changing setting is also easy, just right-click workrave icon on system tray and select preferences.
The Exercises is given when you select exercises in menu or each time the timer is over, just follow the instructions.