With the semester over, I'm cleaning up my office today, and buried on my bulletin board, I found the classic J-Con poster, and I have posted it here, and a little snapshot should show up at left.
I didn't witness this personally, but the story is that this guy was exhibiting these at the NSCA AES show in the 1990's about 1992 (see comment from Matt Stoody). If you can't make it out, it's an "Edison" connector, connected directly to a 1/4" plug. The idea is that you can "save money" by using plain old extension cords instead of "expensive" speaker cables.
When asked what would happen if someone plugged a speaker (or a male 1/4" connector) into a power outlet, the guy selling them supposedly said that this wouldn't happen. Why? Because Jesus would protect them. J-Con supposedly stands for Jesus Christ of Nazareth.
Note: If anyone can clarify/verify any of these details please post a comment.