A themed costume party is a social gathering where guests dress up according to a specific theme or concept. Themes can vary widely, from popular movies like Harry Potter to historical eras such as the Roaring Twenties. The goal is to encourage creativity and fun, allowing attendees to express themselves through their costumes. These parties often include decorations, music, and activities that align with the chosen theme. Guests may participate in contests for the best costume or engage in themed games. Overall, themed costume parties provide an entertaining way for people to socialize and celebrate shared interests.