While playing Civ 5, I was playing a small continents-style map with me on one continent, hills, a mountain pass, a one-tile land bridge, and some more hills leading into the Roman continent. Rome declared war on me, who had many cities and a sizeable army. At the time, I had only one swordsman and a spearman. Since the area was so hilly, and with an ancient ship coming up soon, I stationed the one group of swordsmen on the hill behind the one-tile gap.
After fending off a few of their warriors, the swordsmen levelled up in hill combat and medic, but with only the spearmen to give them a flanking bonus, it seemed the endless supply of Roman legion would eventually overrun them.
Then came the best instance of sequentially-generated awesomeness since I've played Dwarf Fortress:
The Great General Leonidas has appeared! (Seriously!)
With him at our side, and with such high level swordsmen fortifying on a forested, hilly area, the Romans could only send more and more waves of legion to their death. The war lasted for hundreds of years, until one day around 400 AD, Leonidas was joined by none other than Ivan the Terrible! Together they spread out of the mountain pass, razing Caesar's minor cities until they made their way into Rome.
Satisfied with winning the war, Leonidas returned to his beloved capitol of Paris, where he started a golden age. The citizens were so proud of his work they worked extra hard in constructing the National Epic. The Swordsmen who had levelled so much survived, and their kids kept the bloodline strong by bringing sweet gunpowdery retribution to the double-crossing Japanese.