I always see the most interesting gym accessories and one of the most interesting finds that I've recently come across is a Massage Gym Ball ($8.99).
Basically it is just like any other stability/exercise ball, except that it’s covered in little nubs -- My guess is that some people use it to get a mini-massage while doing their exercises on the ball. While I am all for multitasking, I have yet to find the need for this in my own home gym, but I find them interesting to use at the gym. If getting a mini massage while working your core sounds like a great idea, then buy the ball from Amazon.com.
this looks so comfy