“A bell cannot tell time, but it can be moved in just such a way as to say twelve o’clock – similarly, a man cannot calculate infinite numbers, but he can be moved in just such a way as to say pi.” 

– Daniel Tammet, in Thinking In Numbers:  How Math Illuminate Our Lives

22/7 is a close approximation of Pi.  It is two decimal places from Pi.  Because of this, Pi Approximation Day is observed on July 22.  We can all thank Archimedes for this! 😉