My new classroom is the largest room in our school, which is a blessing and a curse. The side wall folds up, opening the room to the hallway. Twice a month or so, there is a meeting or something that calls for this. Sometimes I know in advance, sometimes I just come back to find the wall gone and/or the furniture moved around (though it is always put back before I have to teach again). It kind of makes me crazy, though I am trying to let go of my territorial instincts.
Last week, one day after school, I was fielding weird what-if questions from my student B in the opened up room, when the principal came by.
Mr C, gesturing towards the open wall: "What's going on here?"
B, dead serious: "Oh, we're talking about science."
I could not stop laughing.