He's 12 and calls it his fort, you might call it a club house or whatever. I built it 2 years ago. It's up off the ground 5 feet (enter thru a ladder and trap door) and it measures inside 10'X12" with a 6.5' ceiling height. Has power and light. It's everything I wish I had as a kid.
My son-in-law and I pulled new coax cable in the whole house and also put in cat5e for my network a couple weeks back. While doing this I also dropped the lines outside to run to the fort. This weekend I dug the trench for the conduit run. I'll have my son help me finish this up this week.
Then it will be time to build a sys for the fort. I've got a couple of cases and a new ps. I've got a few old parts laying around and will try to scrounge some up somewhere. I'd like this to be an introductry build for him. I'll work with him but let him do the whole thing. Should be a good learning experience for him and hopefully, get him even more into this area.
I was telling him that he'll have the only fort in the Central Valley here in California with broadband cable internet and cable tv. I just might stay out there myself!