The Daily Challenge is level provided every day with specific scores and modifiers where you can challenge your friends. If you are connected to Facebook, you will see all of your friends who also play the game and their scores for the level.
The top 5 players in your friend group also help generate a Team Score, which can be seen on the leaderboards by selecting the appropriate tab.
Compete against your friends as well as against other teams to see who has the highest scores. You can access the Daily Challenge through the Cascade Today section.