Autodesk purchased Tinkercad in May 2013 (ref) and with Tinkercad you can now export 3D models via Download for Minecraft. Then import the schematic file into MCEdit and finally you have it in Minecraft.
This video is showing how it works.
What’s next? AutoCAD export to Minecraft or DWG import to Tinkercad?
On the topic of “fun” did you know that you can create Spirograph patterns in AutoCAD with Spiro for AutoCAD?