It opposed "Blue team" (United states) and "Red team" (Unnamed middle easter nation).Millennium Challenge 2002 (MC02) was a major war game exercise conducted by the United States armed forces in mid-2002, likely the largest such exercise in history.
What's funny is that the USA lost the first simulation, to... Spam. In particular, the use of suicide boats and overloading the enemy Anti-missile sytems, with estimated US losses approximating 20 000 men.
The Wargame was then restarted and both sides had to follow "Conventional" rules and some specific things were done so that "Red" team's positions were known by blue team. Of course, blue team won.