I CAN JUST FUCKING PAINT OVER MY BEDROOM WINDOWS!
How have I not thought of this one!!?!?! I've spent months trying to brainstorm a more effective/permanent-in-terms-of-damage-but-still-lets-me-open-the-windows/non ugly way to black out my bedroom. (The first method that came to mind: fit aluminum panels with rubber sealing to the inside of the window frame, held in place by clips. Talk about cumbersome. Next idea: remove the glass panel from the windowitself and replace with an equivalent metal sheet. Elegant, but all my windows are double glazed and I'd ruin the insulation effect if I replaced with a single sheet of metal.)
Now that I think about it, why the hell not just paint them--a good thick coat of paint on the glass will perfectly keep out light without modifying much of anything, no? Any problems here?
(Please tell me there are paints that will hold to glass and be opaque. Like, really, really opaque, since I'll obviously want white paint to minimize heat capture. Though I guess I could paint them white first, then a layer of black on top of that?)