AntiRSI is a handy OS X application ideal for anyone on the computer more than a few hours per day. The universal binary application forces you to take regular breaks from computing to hinder the effects of Repetitive Strain Injury. In addition, AntiRSI is smart enough to detect when you naturally pause and take breaks so it doesn't give you too many breaks to the point where you're not productive.
The freeware app schedules 13 second "micro pauses" every 4 minutes and an 8 minute break every 50 minutes. AntiRSI is also available for Linux, but it's most commonly known for the original OS X version. I believe AntiRSI is the perfect companion for WriteRoom users.
AntiRSI is now aware that you were just in a natural workbreak when you click "Take a Break Now". This means the workbreak won't start at zero, but at the time you had been away already. This gives you the opportunity to turn on your iTunes, or do something else, without resetting the break.
You can find the latest version of AntiRSI on the official site. [discovered via Pop Wuping]