3 x30 of each and perform in a circuit (1 set of each exercise until all are complete).
V-Sit http://sportsmedicine.about.com/od/abdominalcorestrength1/qt/V-Sit.htm
Crunch http://www.shape.com/fitness/workouts/routines/individual-exercises/standard-crunch
Back Extension (on exercise ball) http://fitbie.msn.com/exercise/swiss-ball-back-extension-women
Crunch with twist http://fitbie.msn.com/exercise/side-side-crunch-women
Back Extension with twist (on exercise ball) http://www.youtube.com/watch?v=z3TGYE6SfBw
Side Ups (right and left side) http://www.youtube.com/watch?v=QvD1XLdoIc8
Prone Hip Extension (right and left) http://www.coreperformance.com/knowledge/movements/hip-extension-prone-straight-leg-alternating.html
Toe Touch http://www.fitnessblender.com/v/exercise-detail/Crunch-Toe-Touch-Lv-2/3j/
L-Overs http://www.fitness-and-bodybuilding-workouts.com/double-leg-roll-ups.html
Plank to Pike (exercise ball) http://www.youtube.com/watch?v=w7ee_-7ZWR4