ok, having read further, it seems like anyone who was cycling through the 80s and 90s is well aware of the Biopace. What is really interesting is the level of emotion that pops up in almost every internet discussion about these chainrings. Things often degrade into insults and personal attacks...
In any case, Sheldon like them http://www.sheldonbrown.com/biopace.html

Interesting too that some professionals are now using elliptical chainrings apparently.