make a maze a la pacman, give everyone sheets with eyeholes except the one who gets to be "pacman". they have to collect all the foam blocks which will be repurposed into the dots pacman eats. When he picks up the blocks with the special marking on them, he gets 10 seconds to run around tagging/"eating" the ghosts, each of whom has to return to "home base" after being tagged/ eaten. he must collect all the blocks without a ghost tagging him. give three "lives", or just one. ghost who tags pacman gets to be pacman next.
edit - "bonus" - if someone is really kicking butt you can come out dressed as "ms pac man" just to crack the kids up