Got any water bottles, y'know, the kind at water coolers? You can paint African decorations on them or glue African cloth or mud cloth to them to make them into handsome drums. And the kids can have a drum circle because these water bottles make excellent drums. Just be sure to tell them not to "slap" the drums because they're plastic and have no give. If they gently play them, the drums can make some really beautiful music.

Also, have you thought about face painting? They can decorate each other and have fun! Sounds like a really good time is in store.