The Large Glass was one of Duchamp's favourite works. It is distinctly masculine, telling the story of the struggle between a group of "bachelors" trapped on a torturous love machine who must pump away in order to generate energy for the chocolate grinder (or coffee grinder) whose dusty flakes may lure the bride. In the end it is a hopeless struggle.
Many people view Duchamp as an artist who just liked to fuck with people's minds, after all he is most famous for a display of a urinal in the largest art museum in Paris, but works like The Large Glass show that he has always had something more complex to say.
sources I used
http://www.artchive.com/
http://www.georgetown.edu/departments/amer_studies/limit/h31.html
http://www.xrefer.com/entry/437450