Don't you just love it when a simple, silly in-joke escalates into something bigger and everyone can get in on it?

That's what happened when these two lads waiting on the London Underground started what is clearly an old joke that they like to whip out on occasion and started their own self-described 'Epic London Underground Ping Pong Battle' with nothing but their mouths and some imagination. We can think of worse ways of killing time waiting for a train.

Via YouTube