Astronomers challenge - Mesopotamia!
This challenge from the British Museum accompanies a number of interactives on Assyria, Babylonia, and Sumer. Haven't got to play in depth yet, but my they are gorgeous.
Another is Trading Places: 'Your relations are all merchants and they want you to learn their trade. You will work for three different people, buying goods from other merchants in Anatolia, Dilmun and Susa. Your challenge is to be as good a merchant as possible.'