Here are a few crunches to try - I will separate them according to difficulty...

Easy
Regular Crunches - hands behind head as you reach up and forward towards your stomach - keep your chin up, this helps to not hurt your neck.

Medium
Side to side Crunches I dont know the tech term. Regular crunch position but this time with knees together rotate your legs to the left and lay them on the floor together. Now do a regular crunch from this position. Repeat on the right side. Chin up!

Difficult
Toe reach crunch -raise both legs in the air together. Raise your arms up and reach to touch your toes.

Beginners, I would start with 4 reps of 5. Do 5 counts of one crunch rest and repeat doing 5 more and rest until you reach a total of 20.

Intermediate, 5 reps of 10. Doing 10 reps of the same or variations of crunches.

Advanced, right now I dont know I'm still in the middle I do 7 reps of 15.

Believe me there are many more than what I have served up on this plate. I've got plenty more, I've subscribed to Shape magazine. Tell me whether or not this works for you, like do I need to describe them more or anything.

See ya,
Shannon