“The spectacle – exhilaration and humiliation all muddled together, on stage as in life – [debuts this week] in the form of The Sincerity Project. Then, if all goes as planned, it will return with the same cast every few years for the next 24 years – like a live-theater version of the Up documentary films that have tracked a dozen British children since 1964 from age 7 to 56.”