The French 75 (Soixante Quinze) has a disputed history, and recipe, with some factions calling for cognac instead of gin. You can read more on the history at Wikipedia (http://en.wikipedia.org/wiki/French_75_(cocktail)) or an updated version (featuring local gin from Catoctin Creek here: http://goodbooze.wordpress.com/2011/12/30/the-friday-tipple-midnight-in-...

2 oz. Gin
1 oz. simple syrup (or 2 tsp. superfine sugar)
1 oz. lemon juice
Brut Champagne or other dry sparkling wine

With ice, shake together gin, syrup, and lemon juice. Strain into an iced highball glass. Fill with Champagne. Garnish with a twist of lemon.

History here: http://en.wikipedia.org/wiki/French_75_(cocktail)