You can set a pickle aglow. All you need is a couple of wires, a fixture, a pickle, and a devil-may-care attitude towards the electrical integrity of your house.
Pickles serve so many functions in this society. They're a primary food source, condiment, term of endearment, common cat's name, and inherently funny food. Dare we ask them to serve us once more, this time as light source? Yes. They are called to serve, and we must oblige them. After all, they were prepared for this very thing.
What you do when you light up anything electrically, including conventional light bulbs, is completing a circuit of electricity. You must give electrons a complete path to go from a place of high concentration of negative charge to a place of high concentration of positive charge. The only thing that happens in conventional light bulbs that doesn't happen in loops of wire is the electrons are forced through a section with very high resistance to their flow. This resistance garners heat, and the heat gets so intense that the atoms in the material give off light. In the case of conventional bulbs, the section is a tiny filament of metal that is large enough to let the electrons flow through without resistance.
In the case of a pickle, well, it's a pickle. And a pickle isn't ideally suited to electrical flow. When people attach two wires to it (generally the separated and severed sections of an extension cord), the electrons do flow through it, but reluctantly. The pickle allows flow only because it's mostly water, being soaked for weeks in brine, and because the water is nearly saturated with salt. Salt dissolves in water by splitting into its component parts; sodium and chlorine. The sodium will be missing an electron, acquiring a positive charge, and the chlorine ion has an extra electron giving it a negative charge. The ions - charged atoms - ferry themselves to the wires, and pass the electrons between them, creating a courier service that creates and unbroken path for electrons.
However, the pickle provides a lot of resistance, and heats up. This leads to dryer areas, in which just a little moisture vapor remains between the briny areas. Now, when charges get close enough together, they can create their own path - which is why people sometimes see sparks jumping between their hand and a door handle. The electrons leap between the dry spots, heating them up dramatically. This causes the sodium ions to give off light, a bright yellow. This is why, although the pickle is green and most of the light given off by sparks tends to be white, when electricity heats up sodium, we see a nice orange-yellow glow. You'll see the same in a sodium street light, which works in much the same way. Take a look at the yellow in the pickle - when you see that, you'll know you're looking at hot sodium.
Top Image: National Cancer Institute
Via Ask A Scientist.