The choreographed dance, not surprisingly, was captured on film.
Spontaneous shimmying spurred on by commuting ennui? Not quite. The event was a brand-orchestrated flash mob, a gathering (usually precipitated by an elaborate set of e-mail instructions) of large numbers of people in a public place, where some preplanned event takes place to entertain, amuse or generate buzz and publicity for a well-known brand (in this case, T-Mobile). The mobile-phone company pulled off a similar Trafalgar Square sing-along three months later, attracting nearly 14,000 people.