A big sauna with a huge window looking out on the forest and the outdoor hot tub that's big enough for many people to warm up from the cold. This could also be used as a cold pool for dunking after sweating in the sauna.
Check out this outdoor theater! You could fit the whole neighborhood in your backyard! Amazing that you can have the neighborhood over to watch movies in the yard! You can even swim in the gorgeous pool beneath the screen while More - House Today
Turn a small courtyard into a sanctuary by adding an outdoor hot tub! Fun view of spa pool from above. I would have a hot tub like this! It's private and looks so nice rather than those ugly big plastic things.