Cut melon in half and scoop out seeds. Scoop out melon with melon baller, or you can cut into small bite-sized cubes. Place in a serving bowl. At this point you have a choice. You can marinate the melon in a little rum for an hour or more, or you can just continue. If you marinated them, pour off any extra alcohol. Now, place raspberries in sieve over small bowl, and force berries thru sieve to remove seeds. (You can do this with the back of a spoon or just use your fingers.) Add sugar and lemon juice to seived raspberry puree. Pour raspberry puree over melon and chill for several hours.
Serve from bowl, or serve in individual dessert dishes. You can even serve this with a little ice cream or whipped cream. But it's delicious just as is!