Native to West Africa, this berry got its name from its incredible ability to make sour fruits (like lemons and limes) taste sweet instead, when the juices are mixed together. It accomplishes this feat by utilizing a molecule called miraculin, which works by distorting the shape of sweetness receptors on the taste buds. Be careful, though, because although the miraclefruit can distort the taste of sour foods, it does not change the chemistry of the food. Thus, it could leave the stomach and mouth vulnerable to high acidity.
The New York Times says that for all the interesting ways it interacts with other foods, the miracle fruit isn't very exciting on its own. "It has a mildly sweet tang, with firm pulp surrounding an edible, but bitter, seed."