This looks interesting if you have a little builder in your house!  You can download this 3-D Builder app from Imagination Playground for free.

Parents, teachers, and caregivers — try the new Imagination Playground 3D Builder app and watch children stack, connect, channel, build and make their creations come to life.

Bring Imagination Playground into the classroom! Build with the principles of construction and engineering in the quick builder mode. Observe the effects of physics by turning on gravity mode and watch the Blocks take on their real life physical properties. Use the Blocks to understand proportion, geometry, and basic math principles—or just relax, create, and have fun.