In 1962, Jack Nicholson married a young actress named Sandra Knight. The following year, they had a baby named Jennifer. Though Jack enjoyed playing the role of a father, his lack of responsibility led to friction. He and Sandra consulted a psychiatrist who proposed an unusual treatment: Using psychedelic drugs.

The results were mixed: Sandra (whose hallucinations included Jack turning into a devil) found the experience terrifying, abandoned therapy altogether, and turned to religion for happiness and peace of mind. Nicholson, on the other hand, found the drugs "enlightening," refused to quit using them -- and was soon kicked out of the house. The divorce was finalized in 1968.

That's right: Nicholson's marriage was effectively broken up by a marriage counsellor.

[The classic restaurant scene in Five Easy Pieces (in which Nicholson's character, told by a waitress that he can't order toast because of the late hour, orders a tuna sandwich on toast without the tuna -- and answers her question about what to do with the tuna with, "Stick it between your legs") was based on his own experience in a pastry shop on the Sunset Strip (Pupi's). Screenwriter Carole Eastman was told about the incident and put it in the script.]