Challenger is an application, which allows you to take up daily challenges, ranging from "Run 3 kilometres" to "Avoid smoking all day long". It does not only help you to acquire important habits, but is also overwhelmingly fun to use. You can see which challenges your friends have taken and how are they doing each day. Not only that, you will receive achievement badges for taking up various challenges, going on a streak of accomplishing a challenge and so on.