Prosecco with fresh honeydew juice (strained through cheese cloth). Add sugar and lemon juice to honeydew juice before adding to Prosecco.
This was, I think, Drink of the Year from Bon Appetite a few years back.... from BABBO bartender
I am sure champagne would work just as good.
Another good champagne cocktail is champagne and pomagranite juice.
Lastly is Asia de Cuba's champagne drink made with a rasberry vodka/sugar rimmed glass.