Kumquats are often very tart and slightly bitter when you first bite into them, but as you chew them they get sweeter and sweeter. I have found that describing it to kids as being like cry baby gum or war heads candy is a good analogy. It is painfully tart at first, but you chew through that tart burst and the sweet surprise is very worth it. You eat the entire kumquat, peel and all. Kumquats are so great fresh, that I have rarely had enough of them to cook with. I did use them chopped up into a mango salsa with mango, onion, chili and kumquat bits instead of lime juice. It was delicious over a grilled or baked fish fillet. Kumquats would also make excellent marmalade. Finely chop whole kumquats and substitute for the orange in your favorite recipe.
Dates are something that people relate to holiday baked goods and forget about the rest of the year. Dates are very sweet, almost like caramel bites. Dates can be chopped and added to cereal, oatmeal, cookies, cakes and other sweet baked goods. Dates can also be used in savory dishes where an accent of sweetness brings a nice contrast. Try a ham glaze of date puree, clove, cinnamon and allspice. Dates are a great substitute for more processed forms of sweetness. I have used pureed dates to make energy bars or in place of honey or sugar in recipes. It is more dense that sugar, so you might need to modify recipes to reflect that. No one will guess where the delicious caramel sweetness came from.