In the Reality 101 workshop I do for TTOCs we talk about what is in our 'Bag of Tricks' and how we stand out and connect with students in a variety of classes.
I always enjoy hearing some strategies new teachers and TTOCs use. I remember, to this day, a TTOC (sub) I had as a child who drew a parrot on the board. She told us if we worked hard that day she would teach us how to draw the parrot.... and she did! She taught us in a simple, step-by-step way that I still remember and doodle! So, of course, it is something I enjoy doing and when I return to a school, kids REMEMBER me teaching them to draw this parrot!
Something else I have seen done by a TTOC friend of mine (though I don't have the skills to make it happen) is teaching the kid origami... love it!
Here are some more Busy Work Ideas:
(From Substitute Teaching Tricks of the Trade)