My first Star Wars experience was during live news coverage of one of the Space Shuttle Enterprise tests in the summer of '77. (In which the 747 transporter took it up, and then the orbiter detaches and glides back down for a landing.)

I'm not sure if I what I saw was a commerical for the movie, or they ran a clip before the test started. I do recall the newscasters talking about the movie, so maybe it was a segue for discussing science fiction becoming reality.

Later that night, I had a spooky dream where that "Garth Vader" guy was chasing me! ;)