Party horns are festive noisemakers often used during celebrations like birthdays, New Year's Eve, and other special events. They are typically made of colorful paper and have a rolled-up design that unrolls when blown into, producing a loud, cheerful sound. These fun accessories come in various shapes and sizes, often featuring bright colors and patterns. Party horns are popular for adding excitement to gatherings and are commonly found in party supply stores, alongside other items like balloons and streamers.