More to explore:
Dr. Oz workout
Dr. Oz's 5-Minute Workout to Reshape Your Body
A 7-minute HIIT workout!
Tabata Workout | 40 Minutes
28-minute interval workout
Shape Up: How to Do a 1-Hour Workout in 30 Minutes
Do this workout anywhere and be done in just 6 minutes!
7-Minute Workout - but I would do full extensions instead of crunches.
8 Minute Morning Workout
good five minute workout!