Paul Hawken could have used his time at the Denver Sustainable Industries Economic Forum to talk about anything. And he covered a fairly wide variety of topics. But what stood out was his reminder that “people want to play in the fun sandbox.” That sustainable solutions to business and our world should be joyful. Think of the innovation that’s going on in this space, he challenged us. The amazing technology. System-changing ideas. Massive shifts in the status quo. The wondrous problems about to be solved. The human spirit and joy behind it all.