"Miss Brown, would you mind running along to the headmistress and informing her that we have an escaped firework in our classroom?"
-Minerva McGonagall, to Lavender Brown during a Transfiguration lesson (OP28)
"I could have got rid of the sparklers myself, of course, but I wasn't sure whether I had the authority...."
-Filius Flitwick, to Dolores Umbridge (OP28)
"You'll put Dr. Filibuster out of business, no problem."
-Harry Potter, to Fred and George Weasley (OP28)
The students in general act up in rebellion when Umbridge replaces Dumbledore as the school’s head, but Fred and George’s act of protest – wreaking havoc by setting off a whole crate of their Wildfire Whiz-Bangs fireworks inside the castle – takes the cake. Similarly displeased with Umbridge, the teachers do nothing to try to stop or contain the distracting magical fireworks.
All we know is that the day before this occurred was a Monday in April. (OP28)