Pi, the ratio of a circle's circumference to diameter, has played an
important role in the history of mathematics. One of the best references
is Petr Beckmann's book A History of Pi, Barnes&Noble Books, 1993.
There's also a www site:
through the ages. Pi = 3.2, declared
Indiana State House Bill 246. (unanimously passed by the House in 1897, but was tabled in the Senate).