I uploaded this a long time ago and the audio was claimed by copyright, and for some reason I deleted the video. Let's see what happens this time, now that the copyright fiasco has proven fruitless for the big publishers.
If you are interested in the map and scripts used, here you go:
http://www.mediafire.com/file/8nailkz...
It's been a long time since I tested this so this information may be inaccurate, but here goes.....
To play the map, type "devmap get_down_2" into the console. To start the dance script, press the use button anywhere on the map. To stop the script at any time, look down and press use.
There are two scripts at work here: one of them runs on the player (In this video, it is Rosh) and the other one runs on all available NPCs. There is some criteria on which NPCs it affects but I can't remember the details. This is the reason Rosh is slightly out of sync - the script running on him starts a few milliseconds apart from the others. It's just another example of how bad ICARUS is.
As I recall, all of the source files are included in the PK3, so have at it!