Cut the melon off the rind, cut in chunks and put in blender with some water (amount of water depends how strong you want the juice ex less water = stronger). Blend. Add sugar periodically and taste until it tastes good. Place melonjuice to the side for a bit.
Cut lime into 4 quarters, put in blender, add a little water (same thing with the melon juice. less water = stronger. I barely use any). Blend. Strain the lime juice from rind. Use a spoon to move around the rind in the strainer to strain faster. Add the lime juice to the watermelon juice. Put back in blender, and add sugar until it tickles your taste buds. Enjoy.
Optional: For those with high levels of patience, chill in the fridge before drinking.