For Code Geass: In some aspects it's like Deathnote. Smart guy winds up in a situation where he comes across a power that can finally make his goals and dreams for peace realized. He takes on a new identity and takes the world by storm, he eventually even begins to lead his own revolutionary group. His revolutionary group claims to be an order of justice who will wipe out all of those who abuse their power, mainly the country Britannia, and help out those who cannot help themselves, the country Japan, or in this anime, it is known as area 11. The people of Japan are also known as 11s and are discriminated against time from time.
That's as vague as I can be while describing the plot and not giving it away, it's really much, much, much deeper than that and the plot keeps you guessing. It's not predictable at all and the end is probably one of the best endings I've ever seen in all the anime, or any show for that matter that I've watched. Like it would be in my top 3.