I’m alway keeping my eyes out for a different kind of core exercise that I can incorporate into my strength training workouts. I came across this video a few months ago and have been going it a few times a week since. It works your abs, back shoulders and chest in one movement. Check out the video. Actual demonstration begins at the 2:30 mark.
You can easily adjust the difficulty of the exercise by moving the placement of the ball forwards or backwards. This can be done at home when you have a few minutes to kill and only requires a basic gym ball.
I do 3 sets of 12-15 and can feel it nearly everywhere. Give it a shot! you may be surprise at how difficult it is.