crazy dancemoves! - without any reason!

So...
Ok I was at a bar with some friends. The music was... ....let's say "ok" and there were some people standing arround drinking, talking, having fun, but.....
...suddenly - when the music turned from "ok" to "omg! please turn this shit off!" - the people started to get crazy!!!
It felt like fucking "high school musical" became real! They were performing choreographies and the dancefloor turned into a stage full of dancing-freaks!
There were two guys that danced for hours and they looked like they had practiced their dancemoves for years!
Everybody seemed to know exactly what to do and sometimes 10 or 20 people performed a choreographie together without knowing the others!
It was crazy!
What a freak show!