The SparkFun COM-10541 is a five way selectable switch often found as the pickup selector on electric guitars.
The lever clicks through five different positions so you can select from three different inputs and a combination thereof. While this is, strictly speaking, a selector switch (albeit a switch with some strange permutations) It's also very useful as an encoder and by connecting it to a microcontroller you can read five discrete positions from three GPIOs. Check out the connection diagram below for details.
WARNING
