This exact boxelder bug has been attached to a window at the front of our house for a week now. The window is located at the bottom of the stairs, so we all pass by this creature on a daily basis. The bug sometimes moves to another pane for a few hours, but then it comes back to this same spot. You might even be able to see the finger smudge on the glass, where my dad tried to "heat it up, to trick that stupid thing into thinking it was warm enough to fly away." I've also flicked the glass from the inside several times. On the first attempt, I got him to jump a little bit, but he hasn't flinched since.
Don't ask why we don't just open the front door, step outside, and kill it. That hadn't actually occurred to me until just now.