Pick a popular era in American history and have a Flashback Day. Have students and faculty decorate the halls with paraphernalia from the selected era. Find vintage decorations in your school colors to hang from walls, lockers and classroom doors. Students should wear clothes that reflect era selected. Thrift and consignment shops offer great options for Flashback Day costumes.
School communities become more diverse each year; celebrate this idea by having students dress as citizens of different countries for International Day. This idea works easily for students who are from another country or whose parents are from another country; they likely have items with which to create an authentic ensemble. Other students can wear a piece of clothing that symbolizes another country, such as a beret or sombrero, even if they can't make an entire outfit. To round out the day, have students bring ethnic dishes to the cafeteria for others to sample.
Decorate more than just the halls in preparation for the homecoming day--have students dress head to toe in school colors to show their spirit. Hold a pep rally and offer a prize for the student with the most creative school-colors costume.