focusbook
Ever open Facebook to check something but then suddenly, it's hours later and you have no idea why you're there in the first place? Enough!!
Focusbook helps you stay productive on Facebook. When you first open it, it will demand that you specify a goal, and it will remind of that goal periodically, until you close Facebook.
It's not well built by any standard and has some bugs. But I'm finding that these annoying bugs actually make it MORE effective, so I might leave them for now.
DEVS - pull requests welcome