Age group(s) for this birthday party activity:
Preschool and Younger
Elementary School

Cost of birthday party activity:
Usual cost of food and cake.
Cost of paint and decorations for "buildings."
Cost of hard hats and construction aprons.

Birthday party planning information:
Kids can roll up their sleeves to create a whole city!
Decorations: Section off the room with small, orange plastic cones from a sporting good stores. Further section off areas by using yellow and black streamers. Hang yellow and black balloons.
Food: Set up a food stand for your little construction workers. Serve bottles of soda, pieces of fruit, small bags of chips, and sandwiches.
Cake: Decorate a sheet cake to look like a construction zone. Use chocolate frosting with yellow icing. Visit the dime store for a play construction set to use as cake decorations.

Other suggestions or comments:
Activity: Before the party, collect cardboard boxes of different sizes and paint them bright colors. Also, check with your local hardware or paint store; many will offer construction "aprons" for minimal cost. Check toy stores or party stores for children's yellow hard hats.
For the party: Cover a large area with newspaper. Set up the boxes, along with an assortment of markers, stickers, and other craft supplies. Don't forget household items like popsicle sticks and paper towel rolls. Have the kids build skyscrapers and add windows, signs, and door with craft supplies.