I'm sure you've heard of the flash mob, but have you heard of the symphony flash mob? The definition o which is, a flash mob with musical instruments instead of dance. I stumbled upon this link of the symphony flash mob in Copenhagen, an impromptu symphony inside a subway train. Wouldn't that be an unexpected surprise on your morning subway ride?! !
I'd love to witness a flash mob of any kind in person. Have you ever seen one firsthand?