A raft of talented vocalists—including Debbie Gravitte, Mary Testa, Jill Eikenberry and Anthony Rapp—perform songs from flop shows in the latest edition of a series treasured by musical-theater cultists and obsessives. Expect selections from such short-distance runners as In My Life, In Trousers, Two on the Aisle and Rachael Lily Rosenbloom.