Make the House a Home
Ask each guest to bring a gift for a particular room of the house, such as bathroom, bedroom, living room, kitchen, garage, and so forth. Obviously, you can overlap if you have more guests than rooms. Place the wrapped gifts in the appropriate rooms of your house and have guests migrate with the bride while she unwraps them. You're in for some great photo opportunities!
Shape your invitations like little houses, or stick a Monopoly house to each one. Bake a cake or have one made that is shaped like a house (or has a plastic one or a picture of one on it). Make up a plaque that says “Home Sweet Home” for the newlyweds to hang, and give each guest a marker to sign it. Send your guests home with those cute little tiny clay pots filled with a small plant, candies, or a fake topiary.
Use Monopoly money as invitations, or send invitations tied to a brick, or just cut little houses out of construction paper and use different textures and colors of paper and fabric to create the siding and roof of the house.