This tradition originated in Canada in the 1920's when a group of past presidents of the Engineering Institute of Canada asked Rudyard Kipling, the writer, to come up with an obligation and ceremony for engineers. Since then, all graduates of Canadian engineering programs undergo the ceremony and receive an
Iron Ring upon graduation, which is worn on the pinky of the working hand. The Order of the Engineer in the USA was founded in the 1970's to start a similar program in the States.
I'll be going through the ceremony and getting a ring when I graduate in about 2.5 years.