If you want your kids to see that some fruit actually grows on trees (and doesn't just grow on the grocer's shelf), then sign up to pick fruit with Village Harvest. This nonprofit holds 10-15 events a month, of which you can go to as many (or as few) as you'd like.
The concept? Many people with fruit trees can't consume all the fruit they grow. Volunteers from Village Harvest (like you) will go in a group to those houses, and pick the fruit to give to organizations that provide food for the hungry.
Check out their calendar to see upcoming events and locations.
Thanks to my friend Robyn for reminding me about this great organization.