One of the fun projects that I use to get people to try their hand at computer assisted designing (CAD) is to have them make something utilitarian, like a tool. One of the best examples of this is to make an endwrench. I chose making a 9mm end wrench because a 10 mm wrench is fairly common, so with making, a 9 mm wrench I try to hit it home that you can make the tool you need and not just rely on what is available. I teach this tutorial with TinkerCad for a couple of reasons. First it is free! Did I say Free? Yes Free! Second, it runs in a browser so folks do not need to add any new software to their computers. These two issues alone make it a very powerful tool for teachers and students to use in a classroom. Internet access is, however, required.
I have uploaded a video on making a version of the wrench above to YouTube and it is available here: