I think we somehow missed this at TUAW, but I have no idea how. Just in time for everyone to head home for the holidays (and forget their iPod chargers), here's a quick fix solution to get that battery back up and you back listening to The Cars' Greatest Hits. Household Hacker put this together, and unfortunately they say on the same page that you should not attempt this at home if you're not an expert, but all of you TUAW-reading iPod owners out there are experts, right? If you do try this, don't hurt yourselves or your iPods.
How does it work? Beats us-- the electrolytes in the Gatorade might be breaking down the individual cells of the onion, and releasing excess energy as electricity of some kind, but obviously that's just a guess based on my many years of watching Bill Nye, Beakman's World, and more recently, Mythbusters (pop science for the win!).
There is one major problem with this plan, however, and that is that as of right now, onions do not properly install updated firmware for any iPods of any generation. Hopefully, Apple will fix this oversight in the next Software Update.