Earlier this year I was looking through some old comics and was reminded how much I loved the old Marvel corner box designs of yesteryear. I started with a simple sketch X-men and it turned into a fully vectored illustration. I had so much fun with it, that I decided to do a Dikto-esque Spider-man. It soon took on a life of its own and Hulk, Daredevil and the Secret Wars soon followed.
It really helped me through a creative block I was going through, due to the months of being indoors. If I've said it once, I've said it a thousand times, personal projects are crucial to creative health. :)