Inside, keep your body off the ice or ground (the Inuit put their sleeping blankets on top of a bed of sticks and reeds) and create heat-trapping "loft" (it's what keeps you warm in a sleeping bag) by layering a few small blankets or big trash bags, with leaves or crumpled newspapers in between.

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On nights when they have different bedtimes, Ms. Ellis may take an Ambien sleeping pill, which keeps her from waking up when Mr. Ellis comes to bed later.

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