When I saw Dan a couple weeks ago, we discovered a memory that we shared: Science magazine (always published as Science 'XX where XX was the then-current year-- Science '80, Science '81.
This was the first adultish magazine I subscribed to (renewing the subscription was an annual present from my mom), and I think I subscribed throughout the magazine's six or so years of existence. Dan and I both remembered the article that covered the Robert Axelrod iterated-prisoners'-dilemma tournament, the one that found tit-for-tat to be the most successful overall strategy and formed the basis of Axelrod's The Evolution of Cooperation. We also remembered first hearing about AIDS through that magazine-- there was an early ominous cover story, with a headline that said something like "a mysterious illness has been killing gays, Haitians, and drug users-- and it may be spreading into the nation's blood supply."
And the third thing I remember-- and really that's about it, from six years of reading-- is the Alan Lightman columns in the front of the magazine. Many of these were later collected in volumes that ran under the titles of two of the most memorable columns: Time Travel and Papa Joe's Pipe (1984) and A Modern Day Yankee in a Connecticut Court (1986). (The only column I remember as vividly as those two is "A Visit By Mr. Newton.") The memory of those columns means I was one of the first people I know to pick up Einstein's Dreams when it was published-- one of the only times when I was really ahead of the curve on something that subsequently became very popular among people I knew.
A similar story to "I read about the tit-for-tat experiment in my geeky magazine as a kid more than a decade before starting grad school in poli sci"-- in my high school course on Discrete Math (mainly number theory), we briefly studied voting systems and had to prove Arrow's Impossibility Theorem (something I couldn't begin to do now, and I suspect in retrospect that we only proved a selected subset of the overall conclusion-- but I remember cycling and having to demonstrate that cycling would occur). In each case the result vaguely entered my long-term memory, so that when I encountered it in grad school I knew that I already knew that but also knew that I didn't know it at any very sophisticated level and hadn't studied it in college.