Chromodoro adds a productivity timer to Google Chrome
If you spend a ton of time in your browser -- and that browser happens to be Google Chrome, Chromium, or SRWare Iron -- you might want to install the Chromodoro extension.
Once it's active, just click the little tomato to start a 25-minute session. Best of all, the timer works across multiple windows, so you don't have to worry about losing track when you tab between instances.
When your session is done, an alert window opens to remind you that it's break time!
You'll still need a pen and paper to jot down your tasks - there's no note function built in to extension. It would, however, make an excellent addition...nudge nudge!