When you hear the bells ring on campus, that means that people are inside the Mendenhall Bell Tower, where eight bells hang, with a rope attached to each. The bell ringers are assigned to one bell at a time and, starting in sequence from highest to lowest, they ring them in various permutations.
Ringers use a four-part stroke in order to move the bell back and forth through a whole pull. Subtle adjustments in the timing and strength of each of the pulls and checks allow the ringer to alter the interval between sequential soundings of his bell, thus effectively moving its position in the row.
The process is challenging due to the bells' mechanics, but at the same time is a rewarding activity that anyone can participate in at almost any age.
Courtesy of http://fortran.orpheusweb.co.uk