I need a stability ball. A stability ball is a great addition to standard workouts as they help core muscles to activate. Core is what supports your posture and daily functions, but often overlooked and underutilized while working out.
JUST DO IT!: custom printable workout exampley I like that there are stability ball exercises too (see the last 2 exercises on this example workout)! Workout Labs give full instructions on how to properly do the exercises.