13) My all time favorite d*ck-move as DM: A local ancient epic Medusa has started (uncharacteristically) kidnapping people. The PCs go to investigate. They don't know it, but she has been infected by vamperism and is feeding on the locals. Remember, vampires don't show up in mirrors -> hilarity ensues.
14) This one is fun as all the PCs epic power does not help them deal with it: If the PCs are helping out a kingdom fight the enemy armies, they soon find the recruitment of soldiers drying up. A new church has sprung up, it teaches absolute passivism, charity, self control and passive resistance. It has an extremely charasmatic leader. The religion is spreading at an amazing rate and even some military units have put down their arms. The local lord has hung people for desertion, flogged the peasants, but all that does is make him seem and feel evil and encourage the religion more. Do the PCs make martyrs of the religious leaders? Punish peasants who are just sitting there singing songs of brotherly love? If they don't resolve the issue soon the nation will be overrun by the enemy. Are the religious leaders who they seem? PCs will be suspicious, but it is far harder to deal with if they are not in fact evil spies and telepaths sent by the enemy.