The theater was on something of the main square. It was impossibly hot outside and the air conditioned theater brought the pickup trucks much likes moth to a flame (or the opposite of flame whatever that is). Iowa City wasn't by any means the end of the earth. The University gives this town a great flair and a pretty open minded slant. I was less than half my age at the time and aside from the friends I went with from the University, we were decidedly the younger contingent. At the particular scene when Darth Vader really emerges as a very bad guy...you remember?...with Lea and the syringe and "you will tell us"...a fellow stood up about three rows in front on me and hurled a tomato at the screen yelling "GD commie".
To this day I wonder why anyone would bring a tomato to the Saturday matinee.