I grew up right at the end of the "small theater" era - it was a big deal when they installed the huge 21-screen cineplex in our town (stadium seating! dolby!), but it was a bummer watching all the little local places slowly shutter. Gone were the rep screenings, gone were the amber chandeliers and earth-tone carpets, gone were the juddery prints. I definitely miss the vibe of those places, and it's sad that 35mm screenings are almost totally kaput, though Toronto has a few theaters that still do film screenings.
Way more missed is the drive-in, which was right in the middle of town next to the freeway, and it's funny to think about now that they would show some pretty gory stuff there - I remember being told not to look at the screen that was showing the remake of The Haunting. There was something very special about going to the drive-in on a hot summer night and everyone was lined up under this big dark blue sky that would be traced with really vivid colors from all the pollution (ah, central California) and getting snack food from the big, very truly 70s snack bar building that was all buttery tile up to the ceiling. It's a little crazy now to think that my parents would let me wander off to the snack bar or the playground by myself, since I was only five or six, but this was before the 24 hour news cycle. It was legit sad when it closed to make way for a Costco.
Also, not a theater, but my first pinball memory was a Funhouse in the bar area at a 50s-themed diner that my mom would hang out at with her work friends. It shuttered and became a Chinese restaurant, and who knows what happened to that Rudy.