My classroom this year has large windows that bring in lots of natural light. Even with the thin shades pulled down and the lights off, there is enough light that it interferes with anything dark on a SMART board. Anyone have good ideas or something I/school could purchase to make the room darker? The windows are large (8 to 10 feet tall). I think money might not be too much of an issue so I am open to any and all ideas. Thank you!