This is totally awesome. No Joke
It's no suprise that jumbo netting is my most inquired item on this website. Basically, it's just a California King hammock up in a tree. In many respects too, it's even cooler than a treehouse.
Hope you're not afraid of heights
Often you will only see this type of accessory at an aerial park or specialty adventure course. But for the few that have the know how on how to properly install them or even just where to get them, there are good times to behold! Seriously, being 30 feet off the ground with just a net stopping your fall is exhilarating! My only caution in recommending a jumbo net is for the user to have the credentials and experience in it's proper installation. If you're a bit hesitant or a bit tentative about pulling something like this off, I do recommend you get a professional to help with the install.
Ahhh... Time to relax
So you really want to get one of these too add onto your treehouse project? Awesome! I have seen people of all ages able to enjoy a good tree basking 25' in the air. I recommend using Treehousesupplies.com's netting section to source the netting you need. I highly recommend the square netting. Although it's a bit more money, it's extremely comfortable and will allow you to enjoy every single second you are up with the trees.
So grab a good book, pair of sunglasses and enjoy the great outdoors! And when you start to nod off, do a few jumps and rolls. That always gets the blood moving.