The origin and use of the word random as a modifier was discussed in a recent episode, this one I think. In the discussion, Grant indicated that the use of random -- meaning something off the wall, unusual or wierd -- goes back to the eighties, but I can testify to the 70s. When I was an undergrad at MIT (1974-77) we used random all the time in that fashion. Random was rampant!
Yep, MIT even has a dorm called "Random Hall", originally dedicated in 1968 (so the term must have been in use back then, as you can see by reading some of the histories here).
Thanks, Jill. I did not know that!
Dilettante, the histories you linked to say the naming was after the mythical J. Arthur Random.
Yes, unfortunately those histories don't provide any evidence to show if "random" was used with the meaning of "unusual" or "weird" earlier. "Random" may have given rise to the name "J. Arthur Random", which then became part of the story of the dorm name.