When it comes to the (literal) velvet (and bell bottoms) cultural revolution of the horrid hippie era, June 25, 1967 will serve as well as any other date to mark its psychedelic Bastille Day. It was the day of the One World concert, the first global pseudo-event created for international television. In the early moments of the sly and perspicacious new play Love, Love, Love (at the Laura Pels Theatre through December 18), Kenneth, one of two brothers co-existing warily in a dingy London flat on the day in question, explains to the other the momentous nature of the moment: “This has never happened before in the history of mankind. . . . It’s twenty-six different countries, cultures, and languages coming together. It’s remarkable. It signifies a new age of international cooperation.” “So what are they showing then?” asks Kenneth’s congeni ...