When we went up to Maryland to visit Uncle Jeff, Olivia was most impressed with their Nerf chain gun. Yes, there is a nerf gun which shoots... oh, hell, I dunno, a lot of Nerf darts per minute. It's freaking belt fed! Apparently bouncing several dozen Nerf darts off one's cousin's head pretty much defines a good time. I'm not sure, because I was busy bouncing the same off her uncle's. He told me there were mods that made it even more awesome, but I didn't believe him. So he went and proved me wrong.
Ok, just to repeat: A belt-fed Nerf gun. It just don't get much better than that.