Flash mobs are considered a fad by this point, but I just saw a video that I really love.
"Jesper Nordin conducts the Sjællands Symfoniorkester (Copenhagen Philharmonic) in a flash mob at Copenhagen Central Station playing Ravel’s Boléro. This kind of performance art reminds us that, when you least expect it, you can become submerged in beauty within moments: anywhere, by anyone (in street clothes, hauling a bassoon), and it can disappear just as quickly."