To deal with this in the short term we went all night-shift worker with some aluminum foil and some cardboard boxes.
So in honor of my mom visiting for Houston's International Quilt show I decided to bust out the sewing machine and add some light-blocking liners to my current white Ikea curtains.
Yay sewing machine! This project was really straightforward and quick. Mom and I ran to Jo-Ann Fabrics to pick up some blackout liner and it was even on sale for $4 a yard! My curtains are about the width of a standard bolt (54in) and the windows in my room are about 2 yards long, so we just had them cut 4 2 yard lengths for my 4 windows. Hooray no cutting!
This was my set up. I had to clear off my whole huge dining table since I was working with such a large amount of fabric. All I needed to do was wind up a bobbin of white thread and get sewing!
The best thing about this project was how quick it went. I wasn't worried about accuracy or sewing beauty (so of course my lines came out perfectly straight! ha) so the whole process of taking down curtains, adding liner, fitting liner and putting it back up took about an hour for all four.
Below shows the finished result on the left and the original see-through version on the right so you can compare. It looks subtle in these pictures, but the difference in our room is kind of amazing! Think I'm going to have a good night's sleep tonight.