Streamlining PB&J sandwich prep
Dad (who's raising4boys) optimizes his peanut butter-and-jelly sandwich assembly line by making an entire loaf's-worth and then freezing them. I queried him further, because my experience with frozen pre-made sandwiches was terrible, but he swears that with a good-quality bread, they turn out wonderfully. (If you try this hack, let us know how it goes.)
He uses this technique to ease the morning lunch-packing crunch before school, but it's equally helpful during the summer for spur-of-the-moment picnics.