The Utah Teapot was originally created by Martin Newell, back in 1975. It is based on a real teapot, and it was digitised by hand. It became extremely popular because, at the time, there were very few available models. The teapot is a complex model from a mathematical point of view, with both concave and convex local surfaces, saddle points, various degrees of curvature, and almost as important, it is a highly recognisable object. Newell actually built a full tea set, but the teapot was the most used model.
3DModelFree.com provides tons of 3D models, mostly in 3DS MAX. A equally large collection of textures is also available. Please read the license before downloading.