Pillow room: don't spend money on couches or lounge chairs and buy a really nice movie screen. (This would be really fun for movie night, to just move all the living room furniture and bring out the pillows!
Home theater room in the attic. A more do-able idea than those other fancy home theater rooms! Much cozier and warmer than the individual recliners in rows that you see in a lot of fancy home theater rooms
Bucket list: give a shelter pet a loving home. I have already done this, but will continue to adopt shelter animals all my life. It makes me so sick and sad when animals get treated horribly. Save an animal, be their forever home.