Does anyone have unique ideas and/or photos for a small (~14x11) room that can become the ultimate man cave for a guy who thinks, listens to music, and "whiteboards" - like, scribbles lots of ideas on whiteboards?

I'd like the main non-window wall to be painted with idea paint, but the rest of the room outfitted with library shelving, a desk, small couch, chair, etc. I'm totally cool with the room being tight so long as it's incredibly comfortable and everything serves a purpose.