Rechargeable LED lights are great for camping or eating outdoor in the evening. Charge them from your (green) mains supply and then you've got soft portable lighting that will last for hours and hours. Solar powered lights are even easier, just leave them in the sunlight to charge and switch them on at night.
Candela Portable Light Set
These are great lights, but not the cheapest. You get four rechargeable lights that when charged each give off about the same amount of light as a candle which, unlike many LED lights, is a soft and pleasant glow. The absolute business for dining outdoors.
Sun Jar
If you look at the photos you see a bright glowing jar, but in reality they're not as good as that as they give off about the same light as one or two candles. They are however a true eco gadget and I love mine. Take the jar, put it in daylight to charge from sunlight and then at night you've got a groovy looking table feature or night light. If you're looking for portable illumination, get something else, but if you want a night light with the wow factor, this is it.
Bubbly colour changing solar garden lights
There's loads of different solar garden lights on the market, but these are my personal favourites. Stainless steel tubes with a liquid chamber and solar panel on the top. When they come on at night they change colour and the liquid bubbles for a really fun effect.