The Cube is a large cube shaped sculpture next to the Michigan Union which is balanced on one of its corners and spins surprisingly easy for how heavy it is.
Formally known as The Cube "Endover", the sculpture was created by Tony Rosenthal in 1968. It is a gift of the Class of 1965.
More information is available at http://www.public-art.umich.edu/the_collection/campus/central/92
Rosenthal's first cube, entitled Alamo, was installed at Astor Place in New York City in 1967 and is one of NYC's most famous public sculptures. Endover is one of several similar sculptures that Rosenthal created following Alamo. Endover, Alamo and Marty's Cube (at the Boca Raton Museum of Art, FL); all of Rosenthal large-scale alumimum and Cor-Ten steel Cubes rotate.
Check in to the cube on Foursquare.
According to University tradition, the president spins this cube on their way to their office at the Fleming Building to start the day.