When my son, Joe, was in second grade, his very clever teacher introduced the concept of international trade by having students stand in a line, then check the tags in each other's collars and call out where each shirt came from. Our project takes this idea a step further by placing the labels -- as well as those for produce and other items your family buys -- on a map, but both exercises result in spirited discussions about how and why we're all connected to the wider world.
Seek out a wall map that clearly shows the borders of countries. Keep a roll of removable poster tape on hand for securing labels. Stickers (such as those from fruit) can be attached without tape.