Continuing my status bar app binge, I created Sitting Timer, which shows you how long you've been sitting in your status bar.
Download it here (tested in OS X 10.9)
- One click resets the timer. Double-click quits.
- Between 10 and 15 minutes sitting, the text fades from black to red.
- If you're idle for 1 minute, it flashes for 10 seconds to remind you to reset it (if you got up).