Posted this back in 2010, but someone else reposted it recently and it is so good.
(Flashmobs seem to have faded away, haven’t they?)
Anyway, in this case it’s not so much a flashmob as a Random Act Of Culture.
The Opera Company Of Philadelphia have continued to perform these, and if you click through to their youtube page there are renditions of Verdi at a Cheesesteak Diner and Mozart in a Library, among others.
While not featuring the massed number here, part of the treat is that each performance seems out of place but finds a home in strange environs.
Now, if you haven’t seen this you’re in for a treat, if you have it’s as good as you remember.