From Czarek Tomczak:
5 Minute Break is a little program lets you set a timer that alarms you to make a 5 minute break away from your computer. Alarm can be easily set on/off by left clicking program icon in system tray. The icon in system tray has 2 visual states, a blue icon when alarm is off: Five minutes before break a tool tip in system tray will popup, this is so you can prepare for the real break, so when it comes you will go away from computer immediately, with no excuses of like "But I need 5 more minutes!". During these 5 minutes before break you have enough time to save your current tasks and finish any chat conversations.