Rotate using the right/left arrows! Zoom in/out using up/down arrows! Press s to show/hide parameters! Edit: Changed it so it can display the parameters, thanks to dapontes. When changing the parameters, it takes a while before the attractor is reached. The animation shows a part of the curve that moves along the curve. (The Lorenz attractor is a curve in 3D. The rotation here is around the y-axis.)
A longer, static, rotatable curve at: http://scratch.mit.edu/projects/11465897/ The differential equations are described in Wikipedia: http://en.wikipedia.org/wiki/Lorenz_system used at: http://www.malinc.se/math/fractals/mainen.php