I was going through a stack of papers the other day and came across a few things that were a result of this down-time creativity.
Typically I will use whatever material is at hand, such as:
An abstract design made from tracing a found washer and using any color pen or highlighter I could find in the room I was working in.
A rodent copied onto line paper using ball-point ink. If I recall, I think I was filling in for a science teacher and there was a photograph of a rat in the textbook.A psychedelic 60s inspired mushroom from a stray piece of model magic left over in the art room, then colored with markers and ball-point ink from another classroom where I was covering a silent reading block.
And a ball-point ink robot while subbing for a middle school robotics class where each class watched the exact same "Robots of the Future" DVD.