Cardboard boxes + Imagination = FUN

Cardboard Box Fun, these would definitely go over well in my house....

 

DIY: Castle Story Box 

The Imagination Tree Blog

DIY Kids: Ice Cream Shop

Childhood 101 blog

Homemade Card Wash 

Filth Wizardry Blog

Check out tipjunkie post for  

32 Things to Make Using Cardboard Box DIY

 I had to go searching for these, here's a Cardboard House I made for Cy probably 1 1/2 ago out of Refrigerator box:

Cut out doors, 2 windows, doggie door in the back.  Siding was made out of strips of blue poster board, white poster board for the trim and windows.  The window boxes are a shoebox split down the middle and we decorated with flowers and curtains. And of course a mailbox for his mail.