Pokemon and Trainers
There are tons of human trainers for your kids to choose from, and parents can make some pretty cute Pokemon. Major benefit: you basically get to walk around in footie pajamas, and kids can put trainer costumes together after a couple of trips to the thrift store.
Chell, Atlas, and P-Body
Kid as Chell, Mom and Dad as Atlas and P-Body, the robots. This cosplay would be a little more work, but we think it’d be pretty cute.
Princess Zelda, Link, and Navi
Princess Zelda, Link, and the fairy Navi would make a fantastic cosplay set for parents with a baby or toddler.
Looking for something easy to throw together last minute? Have too many kids to know what to do with? Pacman ghosts are a retro favorite, and adults can be Pacman and/or Ms. Pacman.
There are a bunch of birds to choose from in the Angry Birds canon—beware of forcing the pink one on your daughters, though. Especially if you have more than one daughter. It could get ugly.
Minecraft cosplay is easy to make because all you need is some cardboard and poster paint to build all those pixels—and there are lots of characters to choose from!
Plants or Zombies?
Plants Vs. Zombies? Oh yes. We recommend that very young kids become zombies—toothless, bald, big-eyed—I mean come on, you can’t pass that up. Older family members can choose between plants and zombies, and either way, everybody gets to be silly.
LittleBigPlanet is a great cosplay for any size or shape of family, since the characters—Sack People—are fully customizable. You can all create individual Sack People in the game and then dress up as your unique avatar!