TOD - I was in the fifth grade, Thomas Jefferson Elementary School, when the vice-principal came in and made the announcement.
We did not go home until our regular time.
My father's parents, the only grandparents I ever really knew, were taking care of my sister and myself that week. Mom and Dad were in San Francisco for a college reunion (UC Berkeley), which wasn't cancelled because too many people had come from too far away. Their trip was remarkable mostly for the heel of Mom's shoe breaking at one point, causing her to fall keester first into the gutter - not something she was normally known to do.
I don't believe in conspiracy theories much - most conspirators are too sloppy to pull them off.