Abdominal exercises?

I just finished my second day. Day 1 I did a 40 minute workout; day 2 was the first day of my 30 day challenge.
Are there no abdominal exercises? I haven't found any yet. Seems to be a significant gap to me. Also, would be nice to have some stretching at the end to stretch out the muscles that were worked during the workout.|||There is one that I know of as an abdominal exercise, and that's the standing knee crunches, but that's the only one I can think of right now, and I think I've pretty much done all the exercises.
I use Active as a part of my overall fitness/weight loss program, and so I get in ab workouts elsewhere, but I can definitely see how for the many people who will use only Active, it might be a bit lacking in the ab area!|||[i]While there are no "isolation" exercises for the abdominals, believe it or not, squats and lunges use your core a great deal and also burn way more calories. So, if you focus on great posture, those core muscle will be working. More to come, we promise!