The PlayGround Theatre's transformation from an ambitious children's theater to an ambitious adult theater — rechristened Miami Theater Center — should have surprised no one familiar with its previous work. But its debut production of Anton Chekhov's Three Sisters pulled so many avant-garde surprises on its audience that it somehow honored the 1900 text while modernizing it and streamlining the theatrical experience to new heights. The unpredictable, period-spanning costumes, up-close addresses to the audience, modern slang, and music translated Chekhov's timeless words into a more contemporary context. And while choreographing a staggering 17-member cast, director Stephanie Ansin used every inch of the largely unadorned industrial-style space, from the aisles to a sprawling three-room set design, parts of which could be accessed only through an intimate seating area that rotated on a pivot. The complicated and airy mise en scène resulted in some occasional problems with spectators' sight lines, but a spectacular experiment beats out a safe, polite success any day.