It’s been a long time since my last free idea, even though I’ve had a few knocking around my head for even longer. Still, worth the wait I think, this one is a corker. And it has nothing to do with burning my hand on the kettle at work trying to find out if it’s hot or not. Honest
Simple: A sticker, that changes colour to heat (they exist, used to come free with cereals) but more specifically only changes colour when its above 85-90°C (arbitrary numbers right now but hey). You then stick the sticker to the side of your kettle. If it’s changed colour, no need to re-boil.
Tefal could do a whole thing about it, seeing as they have the frying pans with a similar idea.
Or, if that’s too simple and cheap for you. A kettle that has a ‘recently boiled’ light on it, that’ll stay on for 10 mins after it’s been boiled.
Someone please do it, and if you feel the need to celebrate my genius with this simple thinking then mail me: rob AT randomtask DOT co DOT uk.
(I’m sure you can workout the anti-spam action going on there)
randomtask 
I think that you just need to stop putting your hand on things to see if they’re hot 😉
Shhhh!
But also think of the electricity saving! Thats being green that is 😛
Hey Rob – Don’t they already have these things? We had them in Florida to put on the windows to determine outside temperature. It was like a colour spectrum with numbers under the colour bar giving a general approximation of temperature. http://www.t-m-c.com/our_products.html
But it is still a brilliant idea…
Ah, well there you go then, all you need to do is market it as a ‘Kettle energy saving magic sticker thing’ (marketing may have to think of a more catchy title) and the idea’s away!!
http://www.temperaturelabels101.com/
Actually I think that is a better site to refer to – similar products but more of what you are talking about really…
Like those funky forehead thermometers, you know the ones?
As for marketing ideas, not sure I can help you, BUT, I feel there should be many more things (perhaps things already in existance) to be relabelled with the slogan “you need this because you’re dumb” or something to that effect.
New google humour for you:
Random Task. Robs Randomness exposed … getting transformed into inanimate objects using speculative magic.