I have used PVC pipe and the elbow connectors for a wall divider and a clothes rack and they are really easy to use! Tutorial from Angry Julie Monday here (photo on left), finished house using the same pipe and design from.
PVC playhouse, just add sheets! My dad made this for my one year old daughter as a Christmas present, and it has been up in our living room ever since! I purchased some pink and white sheets at Walmart and strung some Christmas lights around the top!