What you need: Digital audio recorder; Olympus VN-801PC, $50
Risk level: Medium
A number of professors base their tests directly on the lectures that precede them. If you find your professor to be of that sort, recording his or her lectures to later study would be wise. However, considering the nature of this list, we’ll say that it’ll also be wise to sneak a tiny voice recorder into your exam room and weave a headphone up your sleeve to listen to the bits of the lecture that you left an index mark on. Oh, ‘cause with the Olympus VN-801PC you can do that.