The Massachusetts colony's militia was known as the Minutemen.  They were called the Minutemen because they were a group of soldiers who could be ready for a battle on a minute's notice.
    The Minutemen were made up of volunteer citizens such as farmers, fishermen, and tradesmen.  One of the most famous Minutemen was Paul Revere, who was a silversmith.
    On April 19, 1775 a British military force marched on Concord to capture the Minutemen's arsenal of weapons.  The British were able to enter Concord but were unable to find the weapons.  As the British marched back to Boston, they were ambushed by large numbers of Minutemen.  The British suffered many casualties at this time.
    This battle caused the Revolutionary War to begin.  After this battle, the Minutemen were able to train many more volunteers and be ready for
other battles.
 

    Some resources and web sites that have some more details are Our Country, written by Herbert J. Bass, published by Silver Burdett Ginn, copyright 1995.
    Another book is The Revolution copyright 1958.
    The web site there is more detail is wysiwyg://92/http://www.geocities.com/Heartland/Ranch/91/98/revwar/Lexingto.htm.