Entrance Hall

"'PEEVES!' yelled an angry voice. 'Peeves, come down here at ONCE!'
…
'Peeves, get down here NOW!' barked Professor McGonagall…
'Not doing nothing!' cackled Peeves, lobbing a water bomb at several fifth-year girls, who screamed and dived into the Great Hall. 'Already wet, aren't they? Little squirts! Wheeeeeeeeee!' And he aimed another bomb at a group of second-years who had just arrived.
'I shall call the Headmaster!' shouted Professor McGonagall. 'I'm warning you, Peeves –'
Peeves stuck out his tongue, threw the last of his water bombs into the air and zoomed off up the marble staircase, cackling insanely."

Beware of Peeves as you enter.