It does kinda depend on what you want to highlight, but here are some lesser-used topics that would be make a good, short anecdotal sort of class:
"Proper prior planning prevents piss poor performance" - The siege of the Chapultepec fortress in the Mexican War, where the 1st Infantry Regiment ran up to the walls in the final assault, and realized they left all the scaling ladders behind in the assault staging area, and had to go back for them and then re-do the assault by escalade...which they ultimately did.
The value of sheer bloody-mindedness and guts in defense, even in a 'Die in Place' situation - The defense of St. Vith in the Battle of the Bulge, which though ultimately falling to the Germans, threw them so far off their timetable that enough forces got into Bastogne to hold it...which would not have happened, but for the sacrifice at St. Vith.
The importance of initiative and momentum in the offensive - The Normandy breakout, aka Operation Cobra, which particularly with regard to the 6th Armored Division and it's companion 8th Infantry Division, was one of the two main US offensives from WW2 Europe that used to be part of the curriculum of C&GS back in the NATO vs. Warsaw Pact days (The other was the Lorraine Campaign, but it was less clearly decisive and a lot more complex, so it wouldn't be too suited for your purpose).