I just re-found a humorous anecdote by John McCarthy on an early LISP demonstration, before anybody knew what a garbage collector was:

The first on-line demonstration of LISP was also the first of a precursor of time-sharing that we called “time-stealing”. The audience comprised the participants of one of M.I.T.’s Industrial Liaison Symposia on whom it was important to make a good impression. A Flexowriter had been connected to the IBM 704 and the operating system modified so that it collected characters from the Flexowriter in a buffer when their presence was signalled by an interrupt. Whenever a carriage return occurred, the line was given to LISP for processing. The demonstration depended on the fact that the memory of the computer had just been increased from 8192 words to 32768 words so that batches could be collected that presumed only a small memory.

The demonstration was also one of the first to use closed circuit TV in order to spare the spectators the museum feet consequent on crowding around a terminal waiting for something to happen. Thus they were on the fourth floor, and I was on the first floor computer room exercising LISP and speaking into a microphone. The problem chosen was to determine whether a first order differential equation of the form M dx + N dy was exact by testing whether δM/overδy = δM/overδy, which also involved some primitive algebraic simplification.

Everything was going well, if slowly, when suddenly the Flexowriter began to type (at ten characters per second)

“THE GARBAGE COLLECTOR HAS BEEN CALLED. SOME INTERESTING STATISTICS ARE AS FOLLOWS:”

and on and on and on. The garbage collector was quite new at the time, we were rather proud of it and curious about it, and our normal output was on a line printer, so it printed a full page every time it was called giving how many words were marked and how many were collected and the size of list space, etc. During a previous rehearsal, the garbage collector hadn’t been called, but we had not refreshed the LISP core image, so we ran out of free storage during the demonstration.

Nothing had ever been said about the garbage collector, and I could only imagine the reaction of the audience. We were already behind time on a tight schedule, it was clear that typing out the garbage collector message would take all the remaining time allocated to the demonstration, and both the lecturer and the audience were incapacitated with laughter. I think some of them thought we were victims of a practical joker.