Nothing quite that blatant. Some fellow named Jack Mehoff was often listed as a production assistant though. The teacher was pretty pissed when they finally noticed it, after someone else pointed it out to them.
Someone else found a few seconds of a porno in a box of donated broadcast tapes, and got their laughs heavily pixilating the image, and using it for a backdrop on a couple projects. That this person reminded me of a character in Videodrome just added to the surreal nature of my college days.