So the next NYCPlaywrights play of the month call for submissions is "subway plays" - the plays are to be set in a subway and then we're going to do the recording in the subway.
This isn't original, others have done things along these lines in the subway, but not so many as you might expect. There's the Darth Vader Subway Ride:
And this one, which seems way excessive for a subway situation:
Who could forget the Sesame Street subway production?
The Taking of Pelham 123 - the hijackers want ONE MILLLLLION DOLLARS! Mwah hah hah!