Okay, so it's raining outside, or freezing, or windy. You've completely zipped up your bivy or single wall tent and are breathing out of a tiny air hole. Or, you've got an overhead vent like the ID Unishelter or Crysallis, or a completely enclosed Nemo GoGo bivy. But you toss and turn at night. You wake up with your mouth away from the opening and condensation all over the torso area.
Now consider using one of these medical face masks that contour to your face with adjustable inflation:
Picture this attached to a lightweight tube that exits the bivy/tent and a rubber band holding the mask to your face. This would send all the moisture from your breath to the outside, would allow you to breath in fresh air, and would allow you sleep in positions that are further from the vent, such as on your stomach.
Great idea or crazy? The tube opening looks small to me, like one could feel a little suffocated, yet this is a medical device used for assisted breathing, so it must allow enough air volume to pass easily in and out. Plus, it has multiple use potential, such as a CPR mask, gravity filter system components, or a small cup with the right cap. Now, where to buy one of these and test it out...