I believe cultural is important. I like to take the idea of "Show and Tell" and focus it on students' cultures. I believe it is important for students to:
1. Learn more about their own individual culture
2. Learn about the similarities and differences of other cultures
3. Increase their public speaking skills
4. Work with their families to learn more about their history & tradition
So instead of students bringing in a random toy or game to show off, they bring in an artifact that relates to their respective culture.
Included in this is a form for students to fill out about the artifact he or she brings in. There is also an audience rubric, where students can give feedback on the presentation as well as a template for a letter to send to families explaining the project. Please feel free to customize this to your needs. This has worked in my 4th and 5th grade classes, and I have my current graduate students (who are also teachers) do this as well.