Okay, it may be hard to fathom given the season, but picture this: you're all set for your day at the beach, just about to head out the door when you suddenly realize you have no D-cell batteries for your satellite-radio boombox. Well, instead of stopping on the way to pick some up and cutting into your tanning time, you could just slip any AAs you have handy into Battery Converters, making them instantly compatible with D-cell gear. Since AA and D cells carry the same voltage, your gadgets won't know the difference, but the AA batts won't last as long because they're, you know, smaller.

It's not the worst idea we've ever heard, but the Battery Converter's usefulness is fairly limited. After all, extra batteries are usually as close as a trip to the 24-hour convenience store on the corner for most people, even if you find it hard to remember to keep extras around. Still, it wouldn't hurt to have a few BCs on standby in case your house is ever surrounded by vampires, and the batteries in your PHaSR rifle are totally drained. You never know…. — Peter Pachal

Brando, via Shiny Shiny