Dan John just released a new DVD, called
There are a few preview clips on YouTube. This one shows a warmup he calls the Dead Bug. It's a little different than the Dead Bug Twists I'm familiar with, but it's a good exercise. It's demonstrated with a kettlebell but you can easily use a smaller plate, too, which is how I learned to do these.
Fun stuff, although I'm not sure I've got $110 to spare for the 4 DVD set.
Unfortunately, the camera doesn't move down to let you see the butterfly crunch. So I had to find you another couple videos of it:
The butterfly situp (as part of a short conditioning workout)
The butterfly crunch (as part of a tone-and-shape six-pack making workout, hah)