Adrenaline Pill Pickups: Except instead of slowing down the game world, they speed up the player, while giving him his crazy super-punch. The result: Everyone trying to gun down the speedy nutter whos' punchign everyone away.
Super Blood: Hit someone with a car? You deserve a little reward, and what better than a bloody mist? Sorta like that particle thing on the Blue page.
Pizza: One person (The Pizza Boy) has a rather large gun, and is trapped inside the Pizza place. Everyone else has to try and kill him somehow. Whoever kills him gets five points and becomes the new Pizza Boy.