When I was teaching 6th grade general music, the unit on opera and operetta was my favorite. Every six weeks, with a new group of 6th graders, I showed "The Pirates of Penzance" in my class and we could discuss operetta, singing, theater, adapting musicals for film, etc. And it was a lot of fun to have a bunch of 12 year olds wander around the school for a few days humming Gilbert and Sullivan in the halls.
Modern Major General is probably the most well known song from the operetta. If you want to borrow the movie, I own it. But I definitely recommend seeing it on stage next time it comes to town. (This has been a favorite movie of my kids since Benjamin was about 3 years old, so it knows no age limit.)