This is a fantastic idea and one that has to be credited to an old MacGyver episode. It's not quite as snazzy as Google's cardboard VR glasses, but it’s a perfect activity for a rainy day.
Microsoft has posted up the following video with the intention of promoting its Lumia devices, but this will work with any smartphone. The beauty is that you can take your creation anywhere you want to watch video, making your viewing area as large as you want as long as the focus quality is good.
What you need: Smartphone, Netflix app, Shoebox, Paint and brush, Scissors, Paperclip, Magnifying glass, Black duct tape, and Felt tip maker/pencil or pen.
I intend to do this later today to wow the family.