dumbledore: attention students! this week we've decided to change the house colours because i lost a bet with professor grubbly-plank. so! your new house colours will be...
dumbledore: hufflepuffs get heliotrope and lemon. don't know how that's gonna look, but hey, you'll be easier to spot!
dumbledore: ravenclaws are looking fashionable in vantablack and 'pinkest pink', not sure how we're gonna manage that.
dumbledore: slytherins get cerulean, just like draco's eyes in bad fanfics. sorry, orbs.
dumbledore: and gryffindors wear tie-dye exclusively now. yes, even your underwear.