Cardboard box: bus

Materials:

• large, rectangular cardboard box (like bulk diaper box) with windows, top and bottom cut out by an adult with box cutters (leaving four walls of the box)
• some of: streamers, sparkles, markers, crayons, paint, stickers, glue
• construction paper (cut big black circles for wheels, little yellow or orange circles for flashing lights)
• glue stick / white glue

Instructions:

• decorate box with wheels, flashing lights, brake lights, etc
• child stands in box and lifts off floor with arms to "drive" bus around the house

Cardboard box: spaceship

Adapted from Andrea Gordon's post.

Materials:

• appliance sized cardboard box (from appliance store) with windows and door cut out by an adult with box cutters
• bike-helmets
• tin-foil
• some of: streamers, sparkles, markers, crayons, paint, stickers, glue

Instructions:

• adorn bike-helmet with tin-foil to make space helmets
• decorate cardboard box in theme of space-ship with above materials
• have child wear "helmet" into space-ship and count-down for blast-off!!

Or, you could simply purchase a cardboard rocket-ship playhouse. [h/t: BoingBoing]

Cardboard box: house

Materials:

• large card-board box with window flaps and door flaps cut open by an adult with a box-cutter (cut the corners off the flaps to make it less pointy and to make it easier for little hands to open the flaps)
• some of: markers, pencil crayons, crayons, paint, stickers
• some of: material scraps, tin foil, glitter, construction paper
• glue stick or white glue for older children

Instructions:

• show how the box can be used as a house (doors, windows etc)
• decorate as desired with materials described above