Irish Lords/Crusader Kings
Wouldn't it be cool to either play the Irish Lords of Feifdoms in Ireland with no High King, setting their policies and coming together to deal with Saxon invasions, famine, rebellion, weddings and alliances, betrayals, matters of honor etc.
Use very rules lite/homebrew system - approximate Crusader Kings the computer game or just real life "You have 200 archers" would be great with me.