Yeah, that's a good one on the Power Bars freezing. I'm interested in finding the answer to warm the air that I inhale on those sub-zero days. I don't like the balakava covering my mouth, need the breath unrestricted. Of course I am riding long distances, and putting in a lot of energy into the ride, so I'm sucking air, and can't get a breath through the damn thing. But then I run the risk of cooling my core with the cold air.
One of my gotchas was winterizing my Camelback. Insulated the tube, but not the bite valve. Gotcha, nothing like riding breathing and trying to unfreeze a bite valve.
My favorite is the icecles that form on my beard at the end of my commute.