Visit Brasa (2107 Third Ave.), Rob Roy (2320 Second Ave.), Flying Fish (2234 First Ave.), and Cafe Campagne (1600 Post Alley) for a progressive Champagne cocktail party and friendly competition tonight. I’m capitalizing it because it will be Champagne proper, son. The only stipulation of the crawl (perhaps we say sashay in this case?): Each bar must use Piper-Heidsieck Champagne and Cointreau liqueur in their cocktail. Take your time and hit the bars in whatever order you wish, $20 well spent for four cocktails featuring a premium liqueur and honest to goodness Champagne. Start at 7:00pm, finish and get your vote in by 10:00pm. Tickets available through Brown Paper Tickets.My preferred Champagne cocktail: I wouldn’t want to muss up the vibrant, green apple punch I get from a fresh glass of Piper, so I’d just swirl a tiny bit of Cointreau in the glass, pour the Champagne and add a long leggedy lemon twist.