A tennis ball is lightly attached to the top of a basketball with double-sticky tape and they are dropped from a height over several feet onto the group. The tennis ball shoots way up. Do the calculation first--if you work out all the multiple collisions, in the limit m_tennis << m_basketball it should go about 9 times as high.
Be careful to have the tennis ball centered as close to the top of the basketball as possible, and not to impart any rotation when dropping. The ball comes off pretty fast--be careful not to injure yourself or others.
Click here for the quick-time movie.