Speaking of cars, I foundÂ myself thinking all weekend about David's idea for "McFuel" made from leftover french fry grease. It's just harebrained enough to be pure genius, but until David actually draws up a business plan andÂ waltzes intoÂ McDonald's corporate headquarters, it'll go un-executed and unknown to the world (except the part of the world constituted by the fine readers of the m_f blog). Unless... unless David registers it with one of the many idea repositories on the web.Â My favorite isÂ Lindsay Robertson's list of Highdeas, because lord knows I've solved all the world's crises several times over while under the influence of something or other, but for something more serious I recommend the Global Ideas Bank. If you're more of an "act locally" person and you happen to live in Minnesota, the state public radio station has put together twoÂ great idea generators on the future of small towns and the "education achievement gap." But for entertainment value, you can't beat the Idea Generator from Roman Coppola Studios, which literally allows you to sample concepts like a DJ (it looks like a turntable and spits out random combinations of two adjectives and a noun). I kid you not, on my third spin I got "ingenious educational magazine," which would be a great new idea if someone hadn't already had it.