Some good game titles, referring to The American Civil War (1861–1865),
make use of the colors of the uniforms worn by the two armies: Blue vs. Gray.
• The Union Army (the North) wore blue uniforms, while
• The Confederate Army (the South) wore gray uniforms.
Example(s):
Blue vs. Gray is an interesting card game that covers the whole span of the civil war.
http://www.BoardGameGeek.com/boardgame/89/blue-vs-gray
Blue–Gray Football Classic was an annual American college football all-star game.
http://en.Wikipedia.org/wiki/Blue–Gray_Football_Classic