My girlfriend wants to join the National Guard?

Soo.. My girlfriend wants to join the National Guard and I thought it sounded like a good idea so i wanted to learn more about it before i talk to a recruiter. What do they do? What's the likeliness that thy get shipped out? She says they only get shipped out to help with disasters like the earth quack in Haiti and if they're a war on U.S. territory. What all can you tell me about the National Guard??