White, blue patterned, or even a bright accent color like red or yellow http://houzz.com/photos/10435177 http://houzz.com/photos/124382 http://houzz.com/photos/44046

What soft furnishings do you have. You could pic out one or two colours as an accent colour and use that as your Base for the curtains. I currently have cream hessian walls and have a duck egg blue and chocolate curtains. I'm currently making matching Oxford cushion covers for the settees . If you can't find what your looking for ready made buy the fabric and have bespoke curtains made for you.

I'd suggest dark red curtains if you need curtains at all -- the windows are beautiful as they are, and I'm not sure whether some kind of blind might not give you the ability to darken the room when you want to. On the wall, if you are real fans of any movies or TV shows, three big posters would be fun. Otherwise, I would still suggest using three pieces of art there of that size, all equal in size and somehow relating to each other. Three floral works, or three works in the same style, perhaps. I think a large plain textured rug in a light neutral from one of the cushion fabrics would tie the space together well. You might also consider a lovely low coffee table on the rug to lay out your snacks and drinks for serious media nights.

When dimensioning a classroom or teaching space, the best rule of thumb to produce both good sightlines and efficient layout is as follows: the space needs to be slightly rectangular, but NOT long and narrow. If X = 1, then Y should = 1.2 ideally, and no more than 1.5. Consider a comfortable space of 12 sqft. per student so if you have 6 students in a classroom then 72 sqft. + teaching space and walking space (60 sqft. or more) so say roughly you need 130 - 140 sqft. of space per class.