Haha, this is a great short example to give to anti's as well.

Two households. One has a sign out front that says "We are a gun free zone." The other has a sign out front that says "We are an armed household."

Then ask: Which home do you think is really safer from burglaries, rapists, and child kidnappers. Now care to explain to me why it's a good idea to have gun free zones anywhere else?