Make play kitchen from old boxes and CDs. It's cute, but not too sturdy, as it's just cardboard. Good use of the boxes, though, and I love that it's mostly recycled products. Old CDs for the burners?
IKEA Dollhouse - Last minute DIY for a sweet Ikea hack dollhouse (made out of 2 IKEA-Rast nightstands and few other materials. AND it's easy on the wallet.