One of the classic flavors in many Middle Eastern, North African, Cambodian and Indian food is the preserved lemon.
Originally used as a way to keep lemons long past the time they were fresh, lemons are basically pickled in a strong brine of salt, sugar, water and lemon juice. (Sometimes other flavors like cinnamon, cloves, peppercorns or other spices are added.)
The flavor is sweet, salty, sour and bitter all at the same time. It pairs great with the strong flavors of the cuisines listed above, but you could use them in any dish that you think might work with them. The rind and/or the pulp may be used to flavor the dish and they can be sliced, diced or cut in whatever way works best for the dish you're making.
They aren't hard to make, but the problem is, they can take at least 3 weeks to make depending on the recipe you have.
But Melissa Clark of the New York Times gives a way to make this unusual flavoring in just about 10 minutes in this article. She also includes a link that tells how you can make them the traditional way. Either way, they last a long time in the fridge, so you'll have plenty of time to try out all sorts of new recipes on your family!