Most Helpful Guy
It would be my home office.0
Most Helpful Girl
Computer room, storage room, I dunno... Another guest room? Library?0
I'd put gym shit in there.
Cinema room with proper cinema chairs, back row exclusively for me and females and a popcorn machine and mini bar in the corner :-)
Gaming-den/airsoft-paintball armory. We're talking an hd projector from the ceiling, two nice gaming stations along one wall, armory rack along the other, preferably a ceiling window.
Another guest room? Nah probably a gym. A small home gym.
I would make it a ball pit. I'm an adult, I can do what I want! :D
A dancing studio :)
A home theater or a game room.
We had one when I was a kid and back then we used it as a den... And later my mom put her sewing machine and stuff there.