I think Narga is talking about DodgeBrawl, yes.
I had a secret(ish) room on either side, where there was a walkie talkie/radio setup. If you pressed a button, an airstrike (complete with jet sounds and all, except you don't see the jet
) would hit the rooftops of the opposite side.
I forgot how I did it, but I remember it was used with an "explosion" entity. I forgot if it came originally with BSP, or if one of my older buddies (anyone know the laughingcheese?) had given me a slight mod for BSP to use it.
Either way, I don't have that entity anymore, since I deleted BSP and whatnot.