Home climbing wall. this would be good somewhere where the noise of you falling/weight of you falling won't be too much! Comments about making a homemade wall here : http://www.reddit.com/r/pics/comments/1w1hib/good_use_of_attic_space/
You’ll have fun with the whole family when you build a home climbing wall! Whether you incorporate it into your home decor as your next amazing kids bedroom idea, build it in the garage to boost fitness for an indoor workout, or put it in the backyard, this free standing rock climbing wall DIY tutorial will make the process easy. Includes cost-conscious project budget and material list.
10 Amazing Outdoor Playhouses Every Kid Would Love
A small structure with a climbing wall, hanging swing, and a little house like interior, children could play house, have an adventure or even just see who could hang the longest if they felt like it:Toys and Playgrounds