When I can’t sleep, I find it helpful to clear some clutter. Nothing too taxing, nothing that takes much thought—but I’ll wander around the apartment and put away anything that’s out of place. I usually find plenty to keep me busy for twenty minutes and then I’m ready to head back to bed. It’s a calming middle-of-the-night activity, and if I wake up exhausted the next day, at least my apartment looks good.