What: When should you let go of the past, and when is it better to hold on even to tragic memories? It’s all about a piano, and a world where ghosts walk. More specifically, the August Wilson play, set in 1936, follows Boy Willie, who arrives in Pittsburgh, tries to sell an old piano that has been in his family for generations. Stars Alan Bomar Jones, Bryant Bentley and Sati Word. Previews Jan. 16-17.