Last night I cut up six limes and three lemons to make lime marmalade (recipe in the old version of Joy of Cooking). The fruit has to soak for about 24 hours -- 12 in water, and then add sugar for another 12-hour soak.
Lime marmalade? No, I don't know what I'm going to use it for, either. But it sounded so luscious, so sparkling, I had to make it to see what it's like. The kitchen smells magical, with all the fruit just soaking away in a big pot.