I'm involved with a great group called Playground of Hope (PGoH). I've been working as an advisor and I've built some things for them, like jigs and the potable knock down crane for installing the roofs on the playset towers. I have also sped up their build process by teaching them techniques like how to level the tower bases before they build the towers, and how to easily layout the build site, as well as many simple things that most tradesmen just know from working on jobsites. Together we have taken most of the builds from a 4+ day time scale to a 2+ day time scale, that is a big difference.
Recently an international school Summerhill donated the money for a playset for a kindergarten and they also helped install it.
They made a great video of the event which you can see below.....
If you look at about the 2:41 mark you can see the crane I built in action.
It is very rewarding being involved in such a great group, they are really making a difference.