I like the Wandering Minstrel idea.
I wouldnt mind there being some Battle of Cartenue (sp?) instance. Survive as long as you can before Bahamut's Mega Flare goes off and Louisouix ports people away. Reward individuals based on how many Garleans you slay, what you slay, individual damage/healing, etc. Or slay some giant Garlean magitek Descepticon before time runs out (and your party gets Mega Flare'd).