GeekAlarm! for Linux   
by Peacekeeper Enterprises, LLC.   

Do you spend long hours in front of your computer? With GeekAlarm! for Linux you can help increase your productivity, reduce eye strain, and allay fatigue. It allows you to schedule breaks every 30, 45, or 60 minutes, the length of the breaks, and how aggressive you want GeekAlarm! for Linux to be when enforcing the breaks. It has a simple GUI interface and also allows you to customize the image displayed when an Aggressive break takes place.