• Roundabout Theatre Company spring gala. Roseland Ballroom, 239 W. 52nd St., nr. Broadway, 7 p.m. Expected guests include Brooke Shields, Michael Cerveris, Audra McDonald, Nellie McKay, and noted troupe-hater Jane Krakowski. The theme of the gala is "Beyond the Velvet Rope." Really? Didn't the Scarsdale High prom committee call that one already? You're a theater theatre company in New York City — your theme parties should involve transsexual prostitutes swimming naked in a 5,000-gallon tank.

• Vibe 150th-issue party. Cipriani 23rd St., 200 Fifth Ave., 9 p.m. Swizz Beatz to D.J.; Doug E. Fresh (yes!) to emcee. The invite says the party ends at one; that better just be a ruse to throw media nerds off the scent of the after-after-party, because if the Vibe party really ends at one, then God is dead.

• Fund-raiser for John J. Harvey fireboat. Xchange, 620 W. 28th St., nr. Eleventh Ave., 6:30 p.m. Excuse us: That should have read John J. Harvey Captain's Cocktail Reception for Cast and Crew at 6:30 p.m., followed by the "First Mate's Arrival" at 7:30 p.m. What does it all mean? Who knows! But it seems a fine excuse to dig up a most excellent piece of nautical humor, Cap'n Cook's Code of Conduct.

Or check out our Agenda listings for tonight, selected by New York's culture editors.