Yes, I said nail. Actually the opener hadn't fallen from the ceiling, but the board that the opener was correctly attached by screws to had fallen from the ceiling. Which it was nailed to.
Apparently the rocket scientists who did the addition to the house in 1992 thought it was sufficient to nail a weight bearing board up to plaster with six nails, four of which weren't even going into the joists above the two layers (fire code) of blue board and plaster skim coat. I'm kind of surprised it lasted 20.5 years before the vibration of the opener worked all the nails loose.
Given the Volvo was now stuck in the garage, I placed a large plastic tote on top of the Volvo which came to which about 2 inches of where the opener was hanging. That way if the opener fell it wouldn't do any damage to the car. And I called for backup. We eventually jury-rigged a spare 2x6 from one side of the garage to the other to hold the opener up, pulled the power fail release and gingerly raised the garage door to pull the car out. (After shoveling the driveway.)
We then contemplated a better solution than just re-nailing the board to the ceiling. While it was tempting to use screws and figure they would hold if we got them into the joists above the ceiling, we decided to use a combination of screws and toggle bolts. Unfortunately the collection of toggle bolts at Chez Wood were all too short (needing to go through the 1" board and the two layers of blue board and plaster). I didn't feel like running our to Home Depot at 8:30 at night when it was snowing. So, I waited to this morning and went to Scwartz Hardware today and picked up some 4" and 6" toggle bolts. After drilling holes to get the toggle bolts up into the ceiling we pushed the opener back up where it belonged using two of the existing nails as guides, screwed down the toggle bolts and put a couple of screws in for good measure.
And of course we had to snowblow a foot or so of snow today. At least it was light.
P.S. We made a note to screw in the board holding the opener on the other side of the garage next week when it is warmer.