I got mine at Target.
I don't use it as often as I thought I would, of course, but it was only around $20 , so I guess that's not as bad as ordering a bunch of videos that never get used!!!
I don't know what sixe it is because I threw the box away, but it is a Living Arts ball that came with a beginners video: a compilation of some ab, leg and upper body work from their videos. I don't think any of them are challenging, though I did buy the Living Arts ab and lower body workouts full length anyway. The ab one is ok.
I used the ball last week with the plank work from Cardio Kicks, and boy was it great!!! You really can do some great ab work with it, and supposedly if you sit on the ball at your desk, you are constantly engaging your abs... I sit on the couch with my laptop, so that is not an option for me. I'm going to try some wall aquats with it today--it is supposed to take some of the pressure off the knees...
I don't have any other ball workouts, but I beleive you can get videos and other stuff at the Spri websit, and Gin Miller and Kathy Smith have a few vids out, too. Check videofitness.com for reviews--I don't think they were glowing...
Wendy