Piano Man

I was sitting at a San Francisco sidewalk cafe, minding my own business, when a large herd of grand pianos slowly rolled along the street.
“Did they fall out of a truck?” the waiter asked.
“I don’t know, but I don’t think so,” I said. “They’re all going uphill.”
The pianos, paying no attention to our comments, continued their slow, rumbling roll up the hill and out of sight.
“Hey, maybe we should tell someone?” said the waiter. “They might cause an accident or something.”
“You’re right,” I said, pulling out a cell phone. “They completely ran that red light.”