Marty Pottenger turns hard facts into drama; her play "City Water Tunnel #3," about a sixty-four-mile-long water tunnel, won an Obie. Her new play is about economic inequality in America. After spending three years interviewing the rich, the poor, and the in-between, Pottenger assembled a revealing work about the role that money plays in American lives. A cast of five portray her interview subjects, anchored by Joe Gioco, who's devastating as a depraved and sickly billionaire. (Dance Theatre Workshop, 219 W. 19th St. 212-924-0077. Closes Jan. 24.)