In 1912, the world famous Austrian gynecologist, Dr. Hermann Otto Kloepneckler, M.D., Ph.D. published the following.
The best engine in the world is the vagina. It can be started with one finger. It is self-lubricating. It takes any size piston. And it changes its own oil every four weeks. Its only a pity that the management system is so fucking temperamental.
http://www.reddit.com/r/reddit.com/comments/ch439/and_the_best_engine_in_the_world_is_nsfw/
(Read the comments on the Reddit link for the real name of the man in the image, and other fine facts.)