This method works best if you have multiple groups. The facilitator lets a person draw two animal cards. All groups then have to design a house where these two animals can live together. Each group writes a number of requirements that the house must meet. Make sure you have two opposite animals, that makes it more exciting! When everyone is ready, the groups compare their results with each other.
Imagine the cards are a whale and a bat. You could claim that there is a large whitewater slide through the house where the whale can swim and a tunnel that hangs on the ceiling where the bat can fly around. You can make it as crazy as you want. Bring it on with all the brilliant ideas.