A co-worker of mine (Jamaican), makes an awesome rum punch. This is his super simple recipe:

Jamaican Rum Punch
2 cups of lime or lemon juice
4 cups Jamaican white rum
6 cups strawberry flavored syrup
8 cups of water

Mix all ingredients together in a punch bowl. Serve over ice with a slice of lime or lemon on the edge of the glass or cup. Add more rum or more water to weaken or strengthen as needed.