Transcript:
PEPPERMINT PATTY: Marcie, I came over because I had to tell you the cute thing Pigpen said to me
MARCIE: I'm not interested in your romance, sir, and I'm very busy practicing the organ
PEPPERMINT PATTY: May all your hemidemisemiquavers be flat!!!
Had to look it up, but a hemidemisemiquaver is the equivalent of a sixty-fourth note, the fastest musical note commonly played. Now we know.