We are watching the 1971 movie "Cold Turkey" tonight and I noticed a euphonium had a nice part in the soundtrack. That is part of the soundtrack's "color" music. Pretty sure there are some small sightings in the marching band scene coming up, too, but it was fun to hear a prominent solo.
It's a good movie, BTW. Dick Van Dyke, Bob Newhart, Bob & Ray, Tom Poston, Jean Stapleton, and several other faces you'd recognize are in it (well, if you're as old as I am). The plot is a PR stunt by a tobacco company that offers $25 million to any USA town that can stop smoking for 30 days. The catch is the entire town has to do this, and the PR man (Newhart) who thought of the stunt was confident no town could get every person to not smoke for that long, so it would not cost them anything. It is set in the fictional town of Eagle Rock, Iowa, and was filmed mostly in the real town of Greenfield, Iowa.