Almost changed the definition of pi. It passed the House, but a professor from Purdue happened to be in the Statehouse on unrelated business the day the Senate voted on it. He managed to convince enough Senators that it was a terrible idea and they absolutely roasted it on the floor.

The Wikipedia article on it is great. “Legislative History” is the interesting bit. My favorite part is this:

An assemblyman handed [Prof. Waldo] the bill, offering to introduce him to the genius who wrote it. He declined, saying that he already met as many crazy people as he cared to.