How To Cut and Eat a Grapefruit
Sharp serrated knife
Cut the grapefruit in half. It's optional, but I sometimes like to take a small slice off of each end of the grapefruit so it will sit flat and not wobble around in my bowl. Then simply cut your grapefruit in half across its equator. If your serrated knife is too short, you may want to use a larger chef knife for this task.
Cut around the perimeter. Using your sharp serrated knife, cut the fruit at the place where the pulp and the rind meet. Instead of plunging the knife in straight, place it at a sight angle with the point toward the center to accommodate the curve of the fruit. Using a sawing motion, make your way around the fruit.
Free up the segments. Carefully slice on either side of each thin membranes separating the segments. I usually start in the center of the fruit and, using gentle sawing motions, work my way out to the pith. You probably won't get all the flesh off of the membrane but that's OK.
Eat and enjoy! Place your grapefruit in a bowl and eat each segment with a spoon. When you're finished, don't forget to squeeze the grapefruit into your bowl and drink up the last of its sweet/tart goodness.