A Mexican-inspired fiesta is a great theme for a variety of events. A fiesta is usually a laid-back affair, often including finger foods like tacos, nachos and chips and salsa. This theme is perfect for soirees that typically take place during warmer months like pool parties or early summer graduation celebrations. Decorate an outdoor space with brightly colored Mexican paper banners, altar candles -- even a piñata! Serve food on festive platters, and mix plenty of margaritas for adult guests. Make churros -- a popular Mexican sweet treat -- and serve them for dessert.