If you are getting stagnant with your abdominal exercises, then it is time to spice it up. Next time you are about to do some ab’s rather than counting them off one by one, time them. Also, throw in some resistance to start getting you out of your comfort zone. You can use a medicine ball, but start out light and then work your way up. When you start to get used to that, then use a stability ball and incorporate the timing and resistance with those exercises.