Sit on your stability ball and use your hand weights for arm work. Just sitting on the ball works out your core. Also, you can use the ball for crunches, as well as lots of other exercises -- they're fabulous!
I actually bought one of the Carmen Electra DVDs.

I haven't tried it yet because my BF's mom is visiting. I don't think it would be an appropriate time to stick it in the DVD player. But, I'm looking forward to trying it, and maybe using some of the moves!