My mantra: if a kid likes it, it will be a hit at a party. That's why mini sandwiches, from the classic PB&J to the more grown-up olive-caper butter and smoked salmon, always tend to do well. To kick things up a notch, use cookie cutters to cut into stars, moons, or other cute shapes. Voilà! A boring, lunch-sack classic becomes an adorably chic appetizer.