2d rolling balls

Hi, I want to make a 2d billiard game kinda like pool, I was thinking about using the new unity 2d toolset, but I can’t figure out how it’s possible to make balls rolling in a 2d game, I mean, they can rotate, but they either rotate left or right, and don’t rotate for example up and down. I don’t know if I made it clear but yeah, that’s it, do you know any possible way to rotate the ball in all axis, even with sprites

http://unity3d.com/learn/tutorials/projects/roll-a-ball There u have something close but u have to edit it becouse now player is controling ball.