Blender3d is a modelling and animation program that's been around for some time now, although it had face some bankruptcy fears recently. Some good news though:
"Today the shareholders of NaN Holding have reached an agreement on the outlines for a new future for Blender. In general it means that a non-profit organisation (the Blender Foundation) will be enabled to execute its plans, including Blender development as an 'open source' or 'free software' project."
So if you ever want to delve into 3d modelling and animation, Blender 3d and Aztec 3d are your free solutions!