I had a cool idea a few days ago, when I was in the car listening to my mp3 player and my battery died. What if built a device that had a female usb connection on the end of a cigarette lighter plug? So you could charge your mp3 device (if it charges via USB cable) so you'll never have to worry about your battery dieing!
Well I thought I was the only person to ever think of such a thing until I looked on google:http://www.google.com/search?hl=en&q=u...G=Google+Search
I bought 3 of them on the very first search result (where they are only $1.10 (for 50+).
Everytime I think I have a cool idea I google it, and end up realizing someone already thought of it!
Just like a website that could tell you what radio stations would be best for your mp3 fm transmitter... well Sirius beat me to it: http://fmchannel.sirius.com/default.aspx