When I stumbled upon the Revolve Water Timer — a garden-watering timer that's solar powered — I thought it was a cool idea. I naturally expected the solar panels to detect sunlight and therefore not water the garden there isn't any… you know, when it's raining. But the Revolve Water Timer doesn't include that feature and rather, merely using the solar panels to power the system. Not bad, but I still have to program a timer, something I'd have to do with any computerized garden-watering system.
Flipping part of the solar panel upwards reveals an LCD screen, where you input watering times. You rotate the sunlight back down to maximize exposure of the solar panels and presumably protect the said LCD screen.
Regardless of its inability to automatically avoid the most common annoyance with automatic watering systems — watering during a rainstorm — it's still a not-too-shabby idea.