Burning Man definitely makes the list of most influential experiences I've ever had. It's sort of a cliche to say "Burning Man changed my life," but in my case it's hard to argue otherwise.
After my first year (2008), some friends and I co-founded Playasophy Camp. It's been a rewarding experience, and I look forward to watching it continue to grow in the coming years.
At some point I may take a stab at describing what Burning Man means to me, but for now I'll just offer my strong recommendation that you check it out (if you haven't already).