Hi,

softbody dynamics are a very non-trivial thing as you could imagine. I would say, that you can somehow write your own flubber-ball system on your own, but in general you should definetely NOT invest too much time to reinvent the wheel on yourself.

I quickly searched the net. The AGEIA PhysX engine supports soft body dynamics. You can get the SDK for free on their site, but you have to pay the full license fee I guess. Then, two other libs came across my way: OpenTissue and FastLSM. OpenTissue is in development since 2001, is still active. FastLSM looks even more promising and you can also download the source for free, though, it is released for non-commercial use only. I guess you have to talk with the creators of the lib first.