I wasn't always this water crazy, but living in Austin made me much more appreciative of the preciousness of the resource. A few trips to Big Bend helped a lot, too.
Anyway, I'm excited about the Waterpebble. Created by Brit Paul Priestman, it:
. . . monitors water going down the plug hole when you shower. Memorising your first shower and using it as a benchmark, Waterpebble then indicates, via a series of ‘traffic lights’ flashing gently from green through to red, when to finish showering. Each time you shower Waterpebble automatically fractionally reduces your shower time helping you to save water without needing to think about it.
I generally take a pretty quick shower but I definitely think this could be really fun for the kids. I'm going to buy one.
From Reverse Garbage and The Guardian