If you haven’t seen some of Improv Everywhere’s videos, they are awesome.  Basically, it is a group of people who go out into public places and do large-scale improv comedy.

In their most recent video, for example, they found several “twins”, got them to dress alike, and had them ride a crowded subway train.  People’s reactions are great.  Check it out:

And in case you have not seen the “Frozen Grand Central Station”, here it is.  It’s my personal favorite: