![Mud Clock Mud Clock](https://uncrate.com/assets_c/2009/04/mud-clock-stretched-thumb-960x640-2602.jpg)
Mud Clock
If you long to play in the mud like you did as a kid, you can get the chance with this Mud Clock kit ($20). Developed by Middlesex University in the UK, the clock uses no batteries and is powered entirely by nature. The kit contains everything you need to get your hands dirty.