There is a company called DIT-MCO that makes continuity and isolation testers, used by the aircraft manufacturing industry and others for verifying the electrical integrity of very large wiring harnesses (think many hundreds or thousands of discrete connections).
I remember talking with one of the founders and the subject of how the company got it's name came up.
He explained that he and his family were originally in the business of making all of the equipment needed for drive-in movie theaters (speakers, wiring, etc)
DIT-MCO stands for Drive In Theater Manufacturing Company:
http://www.ditmco.com/