There's something about salting the rim of a glass that makes a drink seem rather posh, don't you think? This drink is very simple with only two ingredients, it would be good for a birthday party or some such!
Salt & water (for the rim of your glass)
Fill one saucer with water and one with salt
Dip your upside-down glass first into the water, then into the salt
Half fill the glass with grapefruit juice
Top up with fizzy water