What is going on in this picture?!?

Yesterday I had some errands to run downtown, and as I was waiting for the traffic signal at Bijou and Cascade I spied this odd tableau. What on earth?!? It took me a second to figure out what was going on, then I grabbed my camera and managed to get one quick shot through the windshield. For some reason I found it hilarious that these people were pushing a piano across the street in rush hour traffic. So odd! And if you look closely, it appears that one of them is also carrying a violin case. I wonder where they were coming from -- and where they were headed!