Very simple and refreshing. You can skip straining the melon after you have blitzed it if you can't be bothered, it'll just make for a more pulpy drink. I didn't add any sugar (because my body is a temple ha ha) but you can certainly sweeten it up if you like.
Fresh rockmelon (cantaloupe)
Sugar or some other sweetener (to taste)
Blitz melon in a blender or Nutra Bullet until liquid
Strain through a fine sieve
Pour into your glass
Add a little lemon juice
Stir in a little sweetener if you like