Trash Can Cheat

This can be fairly hard to execute convincingly.

1. Type (so your teacher cannot recognize your handwriting if caught) some notes in a large font on a sheet of paper.
2. Attach some tape to the back of the paper and act like you're throwing it away but really stick it to one side of the inside of the trash can.
3. Act like you're going to throw away something (or spit out gum, sharpen pencil, whatever) at some time during the test, and look at your garbage can notes while you're there.
4. Rip off the sheet and throw it away when the test is over.