Go ahead. Take your pick: sink or swim. PLAY Habana Outpost Opening Party What: The ecoeatery kicks off the summer with an open-air market; dunk tank; kids corner; and DJs (by day) and fashion show, live performance, and burlesque act (by night). Why: Summer’s here, todo el dia y toda la noche. When: Sat., noon-midnight. Where: 757 Fulton St., at S. Portland Ave., Fort Greene (718-858-9500). DO The Infamous Four Borough Bohemian Beer Bike Bonanza What: Wear something “festive” to cycle through Brooklyn, Manhattan, Queens, and the Bronx — and celebrate at the Bohemian Beer Garden in Astoria. Why: It’s the beer-master cycle. When: Sun., 1 p.m. Where: McCarren Park, at Bedford & N. 12th Sts., Williamsburg. EAT Little Owl Opens What: Cozy West Village corner spot for steak dinner and wine cocktails. Why: There goes the neighborhood restaurant. When: Tues.-Sun., 6 p.m.-2 a.m.; brunch, Sat. & Sun., 11 a.m. Where: 90 Bedford St., at Grove St. (212-741-4695). HEAR Bargemusic What: Listen to seaworthy music like Mozart and Vivaldi on an old coffee barge on the East River. Why: Whatever floats your boat. When: Thurs.-Sat., 7:30 p.m.; Sun., 4 p.m. Where: Fulton Ferry Landing, b/t Pier 1 & River Cafe (718-624-2083). BUY Caravan Shop Opens What: A brick-and-mortar edition of your favorite mobile boutique. Why: Sometimes fashion gets a flat. When: Mon.-Sun., noon-8 p.m. Where: 2 Great Jones, b/t Broadway & Lafayette St. (212-260-8189).