There is more than one way to skin a cat. Well, that's just gross... There's more than one way to make rum punch. There are so many ways to make rum punch that, um, I'm sure there's a formula to calculate this, but in the words of my man Jake Gaylord, "I was told there would be no math...." There will, however, be mixology.
The word "punch" comes from the Hindi word for "five." The five in question are: spirit, sugar, citrus, spice and water. As long as you employ these ingredients, you will have made punch. The drink itself has a certain romance to it, having been popularized in the 1600's by the British East India Trading Company. It is usually served communally, in a large, wide bowl. I think it's a perfect way to please a large number of guests without too much work during the event.
First thing's first: this recipe calls for grenadine. Don't buy grenadine. Make grenadine. It's easy. It is such a remarkable improvement over the dull-flavored, red-colored schmoo typically sold as grenadine that to use it in this recipe or any other is a dirty shame.
1 qt. Pomegranate Juice (like POM)
2 c. sugar
Boil the ingredients, then cover and simmer for 10-15 minutes. Let cool, then pour into a clean, dry bottle.
Some sources call for 2 dashes of orange flower water, but I think this is optional. Not optional for your home bar is an ounce of vodka, for preservation. There's no point having such a delicious ingredient just to let it spoil!
1 oz. Myers' Dark Rum
1 oz. Bacardi Rum
2 oz. Fresh Orange Juice
2 oz. Fresh Pineapple Juice
1/4 oz. Fresh Lime Juice
3/4 oz. Fresh Grenadine
Combine all ingredients and shake, serve over ice.