Two of my proudest moments:
Medieval: Total War
Playing as the Italians, from the Early start, I had managed to completely conquer the Middle East by the 1250's. It was right about that time that the Mongols decided to show up. The entire Mongol Horde, with the Khan at its head, descended on one of my border keeps with a garrison of only about 300, mostly Militia Sergeants and the like, nothing professional. They immediately decide to storm the castle. I know that my 300 men have no hope against 5000 Mongol horsemen, so I decide to try to make their end as glorious as possible. Milita Sergeants worked doubly well against the Mongols' armor and horses, and killed 3 horsemen for evey one of them that fell, easily.
My general's unit of sergeants also personally fought against the Khan and his bodyguard, and the Khan was killed in battle, along with his heirs. Eventually my men were overrun, but not before they killed an entire stack of Mongols, as well as the entire royal family! With no faction leader, the Mongols splintered into large rebel armies, and were no longer a legitimate threat to Europe. Not a bad showing for a bunch of Italian merchants with poleaxes.
Medieval 2: Total War
During the Britannia campaign, I was playing as Ireland. I had an alliance with Scotland and had just finished overrunning England and Wales. The Scots, however, decided to stab me in the back and sent 2 stacks worth of angry highlanders of all varieties against the stone fort that guarded the northern borders of Irish England. My garrison was only about 150, but the majority of those men were the Irish super-soldiers, the Muire. For those who don't remember, they essentially function like Armored Swordsmen, but they have 2 hp, insane morale and stamina, and frighten enemy infantry.
I placed 3 of my Muire squads (90 men overall) in my "siege box" formation, with the purpose of allowing the enemy to breach the gate and then attacking the blob of troops pouring in on three sides. I also put my remaining Muire squad on the walls with an additional unit of spearmen.
The Scots focused most of their attention on the gate, but threw a siege tower and some ladders my way also. Even though there were only 90 Muire, they simply would not break simply didn't get tired, even though there were over a thousand kilts in front of them. As more Scots were crowding to get through the gate, my spearmen managed to hold the gatehouse, and boiling oil just kept pouring on the Scottish crowd- not to mention the high toll that the arrow towers wer inflicting.
Eventually, one unit of the Scots couldn't take the punishment they were receiving in the courtyard anymore, and the beloved morale failure chain reaction began in earnest.I had kept a squad of light cavalry in back, so they gleefulyl rode out and captured hundreds of Scots. After the battle, the Scots refused to pay ransom, so the prisoners were killed, effectively killing off both armies-over 2000 men. I only lost about 30 Muires in that fight. I've never seen better soldiers in any other Total War game.