today DEFENSE National Press Club Newsmaker Luncheon Program on "New Challenges to U.S. National Security." Participants: Former Senator Sam Nunn, D-Ga. Location: National Press Club, 14th and F Sts., NW, Ballroom. 12:30 p.m. Contact: 202-662-7500 DEFENSE Georgetown University Program featuring Gen. James Jones, Marine Corps Commandant, discussion the "Investment for National Security". Location: Georgetown University, 37th and O Sts., NW, Gaston Hall, 3rd Floor Healy Building. 6 p.m. Contact: 202-687-4328 **NEW**