Just discovered Google Autodraw. It is a sketch tool that allows the user to draw some lines and then have the program "guess" what you are drawing as you progress. Once you see what you are trying to draw in the bar at the top, you can select it and have the program refine what you have drawn.
Not a CAD tool, but perhaps useful for showing others a concept, etc.
Here's the result when I drew a crude table with my shaky mouse control skills:
Grant in Iowa