You know, the kind where you actually had to go out to the arcade and put a quarter (or a few quarters) in the machine to play, the kind that could blow 5 of dad's dollars faster than he could blink? (These console boxes might actually be saving parents money come to think of it...)
Anyway, my favorite:
Rampart! (The four player trackball version) - you built fortresses then tried to blow them up faster than your opponent to grab territory. It was a game of building strategy and the fastest hand on the trackball. It was a blast, always got loud and rowdy with four players, and it always ate up all my lunch money!
Rampage was a close second for the same kind of multiplayer action and the general sillyness of running around as godzilla or king kong, climbing builings, smashing cars, eating people and grabbing choppers out of the air!