I wish I would have done a tutorial for this, but I was really winging it and was in a time crunch (hence the slightly eschew window.)
A while back, I picked up a canvas show curtain thinking I could use it for something. I did use it to recover a chair, but had enough left to make a puppet theater. I just had to add some coordinating fabric to the bottom to make it long enough.
I discovered after I made my hole, and finished off with seam binding, that I needed to add some fusible interfacing to the backside, to keep the window from falling forward. (It actually would have benefitted from a stiffer interfacing, but I was using what I had on hand.)
Ages ago I picked up some old felt board letters and have been able to use them for several projects. I was really glad to have them on hand for this project.
My darling neices were happy with their theater, although everyone also wanted to see out of the window too... so funny.
I'm linking to The Freckled Laundry's Air Your Laundry Party.