The grapefruit is a large citrus fruit that is moderately sour and slightly bitter. It is well-known for causing dangerous interactions with drugs, so be sure to investigate this if you are taking any medication. Pink or red grapefruits tend to be sweeter and have more vitamins than the "white" (yellow) grapefruits.
To serve a grapefruit in the traditional manner, first cut it in half right across the axis. A small spoon may then be used to scoop out the pulp. You may wish to first cut around the center or around the edge, possibly using a bent serrated knife. You may wish to use a grapefruit spoon. If the grapefruit is particularly sour, you might sprinkle some sugar on top.
An altogether different way to cut a grapefruit, preferred for use in salads or dessert dishes, is known as supreme. First both ends (poles) of the grapefruit are cut off, enough to expose the flesh. Then the skin and pith are cut away in strips (it is best to use a serrated knife to make curved cuts). Next the membranes are cut or peeled away from the flesh, leaving bare segments free of chewy membranes and bitter pith. This method is particularly useful for grapefruit and pummelo because the segments are so large compared to other citrus fruits.