Go back to the diagram of the Internet in the Peter Packet Game and take a good look at it. You can get there quickly by heading to Tech World and selecting "How the Internet Works."
Okay, you know all about, well, a good deal about, how the Internet works now. Think of your classroom as the Internet. Your desk and the desks of the other students in your class or club could be servers. Maybe your desk is the Soccer Server, your friend's desk is the Sports' Store Server; another friend's desk is the School Server, etc. Sketch a diagram of the servers in the room (your Internet world) leaving space between them.
Then add some computers that might be connected to each server. The Soccer Server might have soccer teams and players' computers connected to it; the School Servers might have teachers, students, and administrators connected to it; and the Sports Store might have customers, suppliers, etc. connected to it.
Next you'll want to connect the servers to each other.
Title your diagram and be sure to label the servers and computers on it.