I was a new grad student at UC Santa Barbara (where I did my
undergrad) in ~1977. Somebody who I had found for my
committee had just returned from a stay at Bell Labs,
and he told me about this thing called Unix. It sounded
very interesting, so I asked around. It turned out that
the Computer Center, where all computing was done back
then, had a PDP11/45 on which they ran RSTS during the
day, and Unix at night.
In fact, somebody had created a sign in one of the
terminal rooms that said
"Oh say can you C by the dawn's early light".
which very accurately described my life back then,
because I was spending many a night learning C,
and was getting used to seeing the dawn's early
light while doing so.
Not exactly an "Aha" moment, but what I learned
from spending these sleepless nights is what
got me started on a career that lasted ~40 years.
Jon Forrest