New York-based "prank collective" Improv Everywhere have just pulled off their latest impressive stunt, which is well worth a watch if you've got six minutes (or thereabouts) to spare.

In a nutshell? More than 4,000 people took place in the "MP3 Experiment", which involved listening to an MP3 and collectively following the instructions of narrator, Steve The Omnipotent Voice From Above. (Ah, we do like a man with a catchy name.)

Key activities carried out by the crowd included following and high-fiving unsuspecting passers-by, striding round with sheets over their heads and - best of all - taking part in a gigantic water gun battle. What japes!

And if you're in the mood to watch some more hilarious pranks, we think you'll rather like this video slideshow...

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