This guy's locks are heat sensitive and will change from brown to yellow if the water is too hot to bathe in. I would think this would be great for kids, but I can't find anywhere what temperature it changes at. What's cool enough for me is most definitely not cool enough for a child, so I'm left wondering.
This monkey rockin' the golden locks is only $2.63 at DealExtreme...and that's with free shipping! If you check the site, you can click on the pictures and it'll show you the difference between the yellow and brown hair colors.
(As usual, no, I'm not getting paid for talking about any of these funky products. I just think they're quirky.)