Come Together Kids: Mini Marshmallow Shooters (or Pom Pom Poppers) put a balloon over the top half of a stiff plastic cup, with the bottom of the cup removed. Pull of the balloon tie with the pompom inside, and POP!
More Nerf Party Ideas or a few game ideas: Load your gun race Target practices Bullet hunt Race to shoot something Capture the flag game Bowling type game where light weight objects are lined up and they try and knock them over.