I've learnt something - thanks.Army-Navy game: a traditional (all but a few years since 1890) football (American football, not soccer) game played between cadets at the U.S. Military Academy (Army) and the U.S. Naval Academy (Navy) every fall. If this was said on NCIS, we can assume that the speaker was on the Navy team.
Fumbled: Dropped the football while carrying it. This is almost always a bad thing to do. Players are ashamed of fumbling.