Your body is a pretty amazing place to be. Every day things try to make you sneeze, make your nose run, make you cough, or even something worse. Lucky for you, your immune system fights them off - most of the time.
So think of your immune system as the Immune Platoon, a bunch of superheroes battling so you can be as healthy as you can be. Using some great online resources you can get an overview of the immune system, find out how your body responds to an attack on your immune system by playing a parasite game or an immune system game, and even quiz yourself to see what you know!
And you can always contact a librarian for even more info!