not sure is it is a true story, but from what i remember (i did some light wave when 256mb of ram was a decent PC :D ) the story is that when they started to code (coding 3d objects is mind blowing for me) in 3d someone made teapot because of reflections or something like that. and now because they have the code for it and as some kind of homage for it, you can make box, ball and a teapot with one click :D

edit:
found a link about it http://nautil.us/blog/the-most-important-object-in-computer-graphics-history-is-this-teapot