A classic of military leadership training is the Defence of Duffer's Drift, written by British officer Ernest Dunlop Swinton but based on the experience of the Boer War. It is still a classic, but more than a little dated. Fortunately the U.S. Army has taken the Duffer's Drift scenario and updated it in a series of videos, entitled "The Defense of Jisr Al Doreaa." It is arranged as a series of dreams in the junior officer's sleep.
Here is the written pdf version.