Can't Stop the Music -- YMCA scene
Rated PG when it was released in 1980, and it featured co-ed nudity, showering, hot tubbing during this song. Steve Guttenberg, Valerie Perrine, Bruce Jenner and the Village People. Plus, speedos, jockstraps, and short shorts. It's a regular skin fest: https://youtu.be/BV0-_Ez8UZE
The show sounds fun, I will look it up. I was at the Y the other day and often wonder if that song, while cute, actually caused a retreat from comfortable widespread nudity in men's locker rooms. Straight guys were suddenly mortified that anothe guy might be looking at them. A few of us are still OK with nakedness but, for example, gang showers are often replaced by individual ones now, and towel dances are common. (BTW, is there an American Bandstand rating for towel dance music?).
Unfortunately, the anti-nudity thing was already in place a few years before the song came along.
Actual dates:
Montreal -- Jan. 1, 1976 bathing suits required
Cleveland -- still nude June 1978. No longer by September 1978. I was actually thankful for a while to be in a place that was kind of behind the times.
The song YMCA -- 1978