Our neighbors decided that they wanted to build a backyard DIY playset for their kids. They sourced the hardware, and got the plans from here:
http://diybuilds.com/diyplaysetplans/
And we helped them put it up! All in all, the project went a lot quicker than I anticipated...
diy playset
diy playground
diy swing set
diy playsets for backyard
diy kids playground
building a playset