"At least!" Sirius agreed, getting animated again. "I bet some of the others might surprise us. That should be our next mission, once we scout these tunnels. Brooms! And balls. Then we can put the word put the word out and see who wants in! Hell, I'd settle for a school broom right now."
He felt along the wall at the back of the hall for the stone with the chipped corner. It took him a moment, but then snick, a little indentation popped open to reveal a knob. He tapped it with his wand theee times, then gave it a turn. It opened, leading the way into the dark.
"After you, m'lady." He bowed to James, gesturing towards the now open door.