The Making of a Great Moment is, at least the press release implies, supposed to be about a cross-country bike trip. But it turns out that Peter Sinn Nachtrieb’s play at Urban Stages is mostly about other things. Maybe even calling it a “play” isn’t quite right; it’s closer to performance art, or an actors’ exercise, a chance for Bill Bowers and Esther Williamson to try on a closetful of identities, all the while philosophizing about the meaning of art, the meaning of life, the value of performing. Which they attack with great enthusiasm, at times making you forget the banality of much of the material. Is The Making of a Great Moment interesting? Sometimes. But it lacks discipline.