GoalsWon - Human accountability coaching for busy people
Habitica - Habitica is a free habit building and productivity application.
CARROT - Meet CARROT, the to-do list with a personality.
Do It Now - Do It Now is a great mobile app that helps you to create new habits and maintain focus on your goals.
Beeminder - Beeminder
myPoli - Gameified to-do list and habit tracker.