There’s an amazing database of old theaters available at http://cinematreasures.org/theater/ . This searchable subject index is part of a larger site but let me talk about this database search first.
You can browse it any number of ways — number of seats, number of screens, architect, chain, status (open, renovating, demolished, etc.) Occasionally stats are incorrect (one theater is listed as having just one seat) but there are lots of commenters pointing out errors and offering information.
I browsed through the most-recently added theaters and found a list from all over the world including Paris, South Africa, and Oil City PA. Theaters are listed in a table showing name, location, and status. I then went and looked at the listing of demolished theaters (over 5300 of them.) Each theater has its own page with a description and sometimes photo, but lots and lots of great comments. For example, the page for the Shawano Drive-In included information from commenters about when the theater first opened, when its screen was knocked over in a storm, and even a pointer to a Flickr account where the opening ad for the Shawano theater has been posted. Other listings, such as the 10th Street Art Theatre in Atlanta Georgia, have lively discussions in the comments about the exact dates of theater operation, when/why it was closed, etc.
As I noted, the database is part of a larger site, Cinema Treasures, at http://cinematreasures.org/ . This site includes theater news, a link list, a FAQ, and a variety of other classic theater information.
I am very bad at going to movies but even I found myself enjoying the nostalgia of going to Saturday afternoon matinees as a little kid. Well worth a visit.