figured out what butterfly meant: basically cross leg / indian style / diamond legged sit ups.
vaccuum method i'm still lost ong.
also found a new work out i love, rvs ab v ups or ab pull ups.
get down in on your hands, like your going to do a push up (real kind),
place a rag under each foot & pull your midsection up (into an inverted v), strive to use your abs here, not your legs.

Hey there!
Yep that's a really good exercise, bodyrockers do it a lot. Vacuums is a breathing technique combined with ab exercises, makes them more effective. Check out the sixpack challenge on sixpackfactory.com; he explains it in one of his videos!

will do.

Just found another one i like - it's a machine, but i take ab workouts wherever i can get them - rotary torso?... gives a similar pull as doing kettle ball side pulls. very nice, think i'm going to work that one in...