My favorite is the weather station consisting of a rock sitting in a dish suspended by a chain. If rock is wet, it is raining. If rock is moving it is windy. If you can't see rock, it is night. If rock casts a shadow, it is sunny
Thanks! I should have known that it would have a wiki entry. Although, I think some of the rules are a bit meh. "if rock is warm" you're not meant to need to touch it as it's meant for a quick glance kind of tool. also, as it mentions, the rock is a finely tuned instrument, so thank you for not touching.
