There is a standby line for every performance. It technically begins as soon as the last ticket is given out. The Public has staff in the park all day; they can tell you if tickets are still available, or if not, direct you to the standby line.
Unlike the general distribution, in which everyone waiting is entitled to two tickets, the standby line is one ticket per person. So, if you need multiple tickets, everyone in your party has to be present. The staff begin monitoring the line at 6PM and tickets are handed out as they become available.
"You travel alone because other people are only there to remind you how much that hook hurts that we all bit down on. Wait for that one day we can bite free and get back out there in space where we belong, sail back over water, over skies, into space, the hook finally out of our mouths and we wander back out there in space spawning to other planets never to return hurrah to earth and we'll look back and can't even see these lives here anymore. Only the taste of blood to remind us we ever existed. The earth is small. We're gone. We're dead. We're safe."
-John Guare, Landscape of the Body