Growing up the first thing I remember building with my own two hands was a spud launcher, so first primitive is
Mostly cylinders
...
I was working on the Procedural Lava Shader from Fundamentals of Texturing course and the Displacement node seemed to interesting not to try. I just can't believe you can model as much as I have with just a plane and nodes. I'm nowhere close to done where I'm going with this is having a body of water which you can see the start of. I've also added grass and trees with out the leaves. Then there is the volcano in the corner of course, where else would the lava come from. I'm just so blown away with what can be done with just nodes alone. Everything here is done with procedural nodes.
As you can see even the grass as geometry. Its not perfect but hey its good for the first time and its not done yet.