Carefully juice enough Grapefruit (5) to yield a cup of juice and strain to remove any pulp or seeds.
Remove pulp by using a grapefruit knife and spoon. Make sure not to poke any holes in the peel. You will probably only need about 6 grapefruit halves.
Pour the grapefruit juice in a small saucepan and sprinkle with Gelatin Powder (2 package). For color, add Cherry Jell-O® Gelatin (1/8 teaspoon). Let it soak for a minute or two.
Add Granulated Sugar (1/4 cup) and heat until gelatin and sugar have dissolved, about five minutes.
Pour in Grapefruit Vodka (3/4 cup) and Water (1/4 cup) and transfer to something with a pour spout, such as a measuring cup. Place grapefruit halves in a muffin pan to keep them stabilized and pour in the grapefruit juice mixture.
Refrigerate for several hours or overnight. Cut each "cup" in half, and then in half again.
Six grapefruit halves will make 24 shots. To turn it into a drinking game, take a Ruby Red (zone) shot every time your team gets into the red zone. Enjoy! And always drink responsibly.