This may be stretching the purpose of this thread a bit, but I was moving a small subwoofer and heard a rattling. Popped it open and found that the glue on the port had let go. My best guess is the adhesive failed due to thermal cycling since it's in a part of the house that can get pretty cold during the winter.
It's trivial to reglue it, but I was wondering if anyone had any recommendation for an adhesive to use. I don't know what the black plastic is, but I'm fairly certain the tube is some kind of dense cardboard.