Since I don't know if this would fall under triggers, or data editor, I'll ask here... Yay!

During a few of the maps in the campaign and such, you'll see the units (like Zealots, Marines, Marauders, etc.) doing a sort of fanfare.
They'll raise their weapons up and fire or do some other form of cheering.
How is that done?

I think it's their victory or taunt animation. E.g. if you used to trigger to make a unit play it's Victory (or Taunt) animation, it might do that cheering thing.

Just for the information: you can also trigger this as a player on B.net: select a group of units and type "-cheer" or "-dance".

Why do I doubt this...

I think there might actually be a global hotkey linked to making your units dance/cheer. It might only work once the "Score Screen/Return to Game" menu shows up.

I might just be thinking of RA2 though.

I'm not kidding. >_>

But anyways, if you look into Rock Arena's triggers, you'll find how to trigger it: at the very first marine's spawn and when marines jump, the guy runs the cheer animation.

Sorry for double post.

I found this: http://forums.sc2mapster.com/resources/tutorials/1888-data-dancing-sc2/#p1

Also, it is "/dance" and "/cheer". Sorry about misleading you with a hyphen.

Heh, y'know it's pretty funny when a lot of our help comes from linking to rival sites...

1) They ain't rival
2) They are a great source of knowledge
3) Unlike Sixen, I am not afraid to link to something relevant if it isn't part of my own community