You can set it up to start glaring at you when you’ve used too much energy.
Well this little gadget is pretty neat!
You clip it onto the pipe behind your shower head and it alerts you when you’ve been in the shower too long wasting water like you’re the King of England.
There’s a Kickstarter for this awesome little doodad: http://www.kickstarter.com/projects/sprav/sprav-turn-your-shower-into-a-smart-shower
They sync with your phone via Bluetooth (that version is $39) but you can also get a wireless version for $20.
I think it’s a really useful little gadget, a lot of us don’t really pay too much attention to how much water we use, especially when it comes to being in the shower (and especially after a long run in the cold!).