Tinkercad is fun.
Tinkercad is an easy-to-use tool for creating digital designs that are ready to be 3D printed into physical objects. Users are guided through the 3D design process through 'Lessons', which teach the basics before moving on to more complex modeling techniques.
Tinkercad was founded in by Kai Backman and Mikko Mononen in 2011, bringing the first browser-based 3D design platform to the masses. In June 2013 Tinkercad became part of Autodesk, joining the 123D family of products in helping students, makers, and individuals from all walks of life to design and make the things they imagine.