In winter, take a lone captain to the north of the map. Leave him there, but keep an eye on him, because apparently he starts shearing a sheep and then eats it.

Instruct your captain to invent something, then pause the game. Put the game speed up to full and wait a couple of minutes. Now unpause the game and the captain will have kept inventing during the pause!

When you wish to invent in double quick time, click Invent, and when your men leave, click on it again. This often makes a catapult immediately. This cheat works only once on each island.