I am teaching animation basics to high school students.  Here are some of the examples I have used and examples I plan on using.

The first example is a really really crudely done ball bounce.  Before I made the ball bounce they had zero ability to visualize what I was talking about.

The next thing I taught them was the leaf test AKA the feather test.  Here it is, also fairly crude.

Here is a more fun (hopefully) project to teach the kids.  I want them to do a morph between 2 objects.  In my case I did a whale to a boat.  But since it is a very basic class I will instead likely have them morph a circle into a square or a star into a circle, just morphing shapes to start.  This assignment is also good because we have only 5 computers for 12 kids so I put them in groups of 2 and have them take turns drawing the frames.

This is the walk cycle I will show them, I doubt they will get this far but if they do HOORAY!