I've got a good one.
Marianne had a geass that could see the future of anyone who met her gaze, she saw that ledouche would be killed in the future, so she tries to die in his place. When she dies, the geass is transfered to Nunnally, who breaks down as she see's the future of everyone around her, including lelouche's. That's why her eyes are shut all the time. Anyways, near the end of the anime, nunnally will open her eyes again, after learning that lelouche is zero, and perish trying to prevent his death by the hands of suzaku. suzaku kills her, thinking that she's out for his blood, then goes nuts, kills the emperor, kills lelouche, and kills himself. then C.C. comes out of nowhere and KEIKAKU DOORI.