After fighting fogging/frosting glasses this morning at -12, I came home for lunch and fabricated a windscreen out of a paint-tray liner, duct-taped to my helmet. It came down to about my nose, and was a definite improvement. Can't say much for the looks, though.
In the summer I'll nose-breathe through the clouds of gnats, but for the occasional swallowed bug I just let it happen. Just protein, right?