An eternal candle sounds like something from a fable, and yet that's what the Wickit, a fragile piece of thin plastic promises.
Just insert a scrap of paper into the device as a wick and then float it on some oil. Once the paper has absorbed some oil you light it and it will burn a bright, smokeless flame for hours. An inch of oil (rapeseed, sunflower, olive) will burn for 15 hours.
A litre will keep you going for 1,000 hours. Use any container you like, from a champagne flute to a galvanised bucket. Just €5 for a lifetime's light that works indoors or out. See wickit.ie