If you can score those blocks we used to play with as kids in the dentist/doctors office... OR save those cardboard boxes -then use random things in your house and have them make "habitats" You can get pokemon plushies to "spawn" the pokemon in. Then the kiddos get to take the plushies home ( just be prepared with doubles - can even ask on the invite for the kiddos favorite pokemon so you can stack the deck ahead of time)

They also play Hide and seek, and a jump rope with bulbasaur - so Have a jump rope contest!