There are some great quotes in that video. The one that Bethe highlights on her blog is "In order to succeed in the real world, you have to be able to fail." I love that one, too. But echoing in my head was Dr. Ginsburg's summarizing comment: "Trust in childhood. Understand that play is the work of childhood. Understand that children are able to find a lot of solutions themselves."
That's why offering a classroom full of opportunities to play and explore is so important to me. When I lead conferences with other teachers, I usually give them a handout that gives reasons for play.
Through play, children...
explore their world.
try out their skills.
hear and experiment with language.
practice using muscles, both large and small.
test new ideas and activities. (And maybe fail)
problem solve. (Practice creativity)
discover how to get along with others.
Through play kids can grow into confident and competent individuals.