We've all heard of the five-second rule when having dropped food on the floor—if you pick it up before five seconds have passed, it's safe to eat. In recent years, scientists have put that folk wisdom to the test and the results fell somewhere in the middle. If bacteria are present on the floor, researchers found that five seconds is plenty of time for it to attach to your food. However, most floors harbor very little bacteria, so unless you're unlucky enough to drop your toast on a tiny patch of e. coli, you'll probably be fine to eat it. If you were to drop that bread on your keyboard, though, that's another story. You'd maybe want to back away slowly and reach for the nearest tongs.

Marvin Birnbom started selling WWII surplus in 1947. That business has grown into surplustraders.net, which offers more than 900 pages of deeply discounted electronic overstock. The site lists both bulk deals—1,000 AA batteries for eight cents each, 10 keyboards at $4.50 per—and a few individual items (12.1-inch LCD screens for $89 apiece). But Birnbom, a hobbyist himself, will sell you any quantity of anything as long as you meet the $30 minimum order. Just give him a call: 514-739-9328.

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