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!
"Love the slanted window" Bonus Room Design Ideas, Pictures, Remodel, and Decor - page 2
Inspiration: A Personal Cyber Attic
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