So, would you like to use an app that "reminds" you to take breaks at the proper intervals automatically (you know notify things). If so, then you should consider installing Tomighty. It is written in java and basically a Timer application but when set-up properly it can boost your productivity as well.
|"Wanna take a break something?.." What!, in English please :P|
*. Sound notifiers.
*. Show remaining time in system tray.
*. Support themes.
*. Always show/hide the timer.
*. Change the "time to take a break" duration according to your preference.
So if you're interested you can download it from this official Tomighty site. And for the GNU Linux users make sure to download the "Jar" file.