In the 1963 comedy classic film "It's a Mad, Mad, Mad, Mad World" the intermission actually played an integral part in the plot. I didn't realize this until not many years ago when I finally saw the film in its proper 70mm format in a theater that ran "police calls" voiced by Spencer Tracy and William Demarest over the theater PA system (even in the restrooms) that actually advanced the plot! Up until then I had no idea that these existed, and offhand I don't know of any other film that did this.