Improv Everywhere took the scene from "A Christmas Story" where Flick took the "triple dog dare" and stuck his tongue to a frozen pole and it stuck, and recreated it on the New York City Subway. 

That poor kid needs a tetanus shot after that.  Not really it was a fake magnetic tongue- A Christmas Story in Real Life behind the scenes.

Here's the original scene.

Man, I cannot wait for 24 hours of "A Christmas Story"  It starts at 7pm on Christmas Eve on TBS-Very Funny.