International Monetary Fund

The International Monetary Fund has some good resources that can help you help students gain an understanding of global economics. On the IMF education page you can find resources for middle school students and high school students.
One of the middle school resources is a game called Where in the World & What in the World is Money? For high school students Monetary Mania is a game in which students can test their knowledge of economic theories.
Teachers will find complete sets of lesson plans for teaching lesson economics to middle school and high school students.

If you're in need of a good visual representation of the World's economic outlook, check out the IMF's Data Mapper. The IMF Data Mapper allows you to see the current, past, and predicted distribution of wealth around the world. Use the slider tabs on the IMF Data Mapper to change the map's display.
Other Links:
Understanding the Financial Crisis - Say it Visually
Saving Money in Plain English
Economics for Elementary School Through High School