Here’s a cool way from Equa System (via Digg) to know how hot the water coming out of your taps is (there must be an easier way to say that):
Here are some more links on related light-coded home gadgets: LED faucet light, a $15 device that makes your water appear bright blue, temperature sensitive faucets from Hansa (via Engadget), the Krystal Electronic Light Showerheads (also via Engadget), and the KWC Eve Faucet (“sensuous light play” in the kitchen).