The Big Apple Circus takes over City Hall Plaza with Play On! (April 4-May 10) -- what better, or more wholesome, way to cast off winter's gloom. Also this month, Charlotte -- of Charlotte's Web -- is one of the great mothers, not to mention friends, of all time. Merle Perkins plays the helpful arachnid in the Wheelock Family Theatre production (April 10-May 10); Robert Saoud portrays her porcine buddy Wilbur, and winning young Grace Brakeman his champion, Fern.