The funniest thing I've ever seen involved a unit of Turkish infantry and a seige ladder. The Turks had climbed the ladder and attacked my spearmen on the walls, but had come off worse and decided to run away, by climbing back down the ladder.

My spearmen in turn decided to chase them, but not by climbing down the ladder after them. Instead they ran down from the walls out the gate and attacked them as they reached the bottom of the ladder.

At which point the Turks turned and began to climb up the ladder again. This time the spearmen decide to chase them up the ladder and so the battle ended with the Turks on the wall and my spearmen assaulting them from below.