I once ran a one-shot for an entire high school class and their English professor (she agreed to this, so long as everyone spoke in English).

The game of choice was Alta Inseguridad ("High Insecurity"), a basic Spanish game with no fantasy or sci-fi elements. Because there were so many students, I divided the class into teams and gave a Player Character to each group. Each team made collective decisions about their character, with people taking turns to act as the PC's "voice".

The game began at a former professor's funeral (much laughter followed this description), and events quickly led to a murder mystery, complete with a corrupt businessman dumping toxic waste near a popular beach, an odd henchman chasing them, and a violent climax that ended with a rather happy ending.

All in all, some liked it more than others, but this was not a surprise. The team format was a novelty for me, but it worked out quite well. The story was something they could easily relate to, which was a big plus.

How much time did you have?

A couple hours, IIRC. English was the last class of the day, so we were able to stretch things out a bit.

Didn't know that. Sounds cool.