This has to be one of the coolest APIs I've ever seen, from both a geek and data standpoint. I love that you can pull story-arcs and issues by author or artist, or even specific collaborations. I'm thinking, Next Glass for Comics.
I'm not a major comics fan, but I did grow up loving the X-Men universe. That aside, this seems like a truly incredible API. I can only imagine the cool apps that are going to start showing up in the years to come!