Here's a refreshing, day drinking cocktail for this scorching Independence Day. It's also a nice use of your good vermouth - which only lasts 2-3weeks in the refrigerator after opening (it's just like wine in that way except it lasts a little longer because it's fortified).
Mother of Pearl (I've been listening to Roxy Music)
2-3oz Dolin Blanc Vermouth
4-8oz Mineral or Soda Water
Add both to an ice-filled glass. Garnish with mint and frozen grapes (I used the sweet Muscat grape).