Fitbit has released an updated version of the app for Android phone that, while mostly focused on fixes and improvements, also brings a new look to the exercise tracking of the app. The updated build is version 2.15 for those keeping score at home and it is out in the Google Play Store now. If you have the app installed you can expect the OTA update at any point over the next couple of days.
The Fitbit app has always had a exercise log where from the main page you could enter in exercise (or sync it from another app if you log elsewhere (I log in MyFitnessPal personally and have it sync)) and see in a calendar form how you did for a particular week. That information along with minutes exercised and calories burned is still there, but now you have a weekly challenge that you configure to help you stay on task of getting and staying healthy through exercise and a sensible diet.