Back on September 9, 1947, Grace Hopper, a Harvard computer scientist, was running tests on a calculator and found calculation errors. She did some investigation and found a moth that had landed between two solenoid contacts, shorting out an electromechanical relay. Apparently, the bug had been attracted by the warmth of the machine.
We now commemorate this occasion every September 9, Tester’s Day.
９月９日はテスターの日なんですって。今年のテスターの日は過ぎてしまったので、来年（だいぶ先だけど）テスターの日にあわせて、バグ供養的な Developer Meetup なんてどうでしょうか。