Below are a few examples of this.
A cube into a wedge
A cube into a periscope
The above gave the necessary skills like extrude, attach (join in blender), Weld (remove doubles in blender) and using the 3d cursor.
Next I had to take those skills learned to start creating a Mayan Pyramid.
This Tutorial added to further skills like Edge loops, and arrays. I was then asked to go off and make some things using primitive objects and the skills learned of things around the house but to keep it simple.
So as per I went overboard. I decided this would be a great opportunity to create some place holder game assets.