More to explore:
The Single BEST Abs Exercise (Scientifically Proven)
by PerformanceU on Youtube
Best Ab Exercises - Our Top 10 Abs Exercises - Fitness Magazine
Abdominal workout: Get flat abs in weeks with these abs exercises
Full Ab Workout
These are some really good exercise to do on your exercise ball.
maybe i'll try this...
Screenshot - Ab fitness exercises - Lose belly fat and get abs