I just took a look at this video Craig Ballantyne did with 6 different abs exercises – and not one of them is that horrible spine-twisting crunch.

• Plank – this is found in many of the TT workouts and it’s actually my first answer when people ask me if I can recommend any good abs exercises. It’s so easy to demonstrate, it’s easy to learn and you don’t have to change clothes first to do them. In fact, all you need is a floor
• Side Plank – this as well is found in many of Craig’s workouts. In TT AAA Abs he’s got a variation called Side Plank + DB Lateral Raise which incorporates some of the “resistance to rotate” he talks about during the last exercise.
• Stability Ball Plank – I can’t remember having done that exercise yet, but I’m pretty  sure I’ve done its big brother exercise – the Stability Ball Plank Rollout.
• Stability Ball Jackknife – this as well is a staple exercise in many of Craig’s workouts – you can do them with your hands on the floor or with your elbows on a bench
• Stability Ball Rollout – It seems so easy when you watch Craig demonstrate it in the video, but it’s one of those exercises where your core is really felt (especially when rolling the ball in)
• Plank Rotation – this is the first time I see this exercise, but I bet it’s effective. It should be since it’s actually 3 exercises in one – regular Plank, Side Plank and then the rotation from one to the other.