Mario and Luigi Mario was saved by Luigi in 2012's Luigi's Mansion, Dark Moon and in it's Prequel. They've been known as brothers since Luigi came out, and hopefully will stay that way. Brothers forever.
Purchase plastic or chocolate gold coins and hide them all over the party area. Give each child a Mario-themed favor bag. When you say, "go," the children have to find as many gold coins as they can. The player who finds the most gold coins wins the game. All players can keep their gold coins to take home as a party favor.