Project idea:  Simple workout app that has multiple tabs. 
1) exercises
   - top level tab shows categories of exercises
   - sub level shows list of exercises for each category
2) workouts
   - top level tab shows categories of workouts
   - sub level tab shows list of workouts for that category
3) favorites

Exercise - one single specific exercise, like a push-up.  Will have detailed info view containing instructions, image, and any other relevant info.

Workouts - workouts is a collection of exercises with specific order, rep/sets or time interval depending on the exercise.  This will show a table of workouts available, clicking on workout will show the exercises within that workout

Favorites - shows a list of your favorite exercise/workouts.