Collaborative Activity for Middle-school students

I am looking for any ideas for a fun collaborative project for students in grades 5 through 9. The activity's project name is New Horizons and is being developed for our students to become more in touch with other peoples and cultures. The school I work in is in a small rural district without much diversity. We have 250 students from K-12 and need activities for afterschool programs.
I would appreciate any suggestions or efforts to collaborate!