A LITTLE CRAZY: Seal is a riddle wrapped in an enigma married to Heidi Klum. Is he pop, reggae, old-school soul? He'll be at Radio City Music Hall with another genre-defier, the now-he's-jazzy-now-he-isn't Peter Cincotti. 8PM.
WORD UP: Strunk & White's Elements of Style is the bible for everyone from writers to teachers to word nerds all across the English-speaking world. Authors (Roy Blount, Jr., Lauren Lipton, others) descend on the Museum of the City of New York to celebrate the tome's 50th anniversary. 6:30PM.
SISTER ACT: Squint and you might see it, listen for the trills and growls at the extremes of her singing register and it might sound familiar: Maude Maggart is Fiona Apple's sister, but the comparison ends there. She's made a name for herself breathing new, heady life into the Great American Songbook. Oak Room, 8:30PM.