I enjoy making covers for many of the series posted. It scratches a creative graphic-design itch that I don't regularly get to scratch. They are regularly inspired by (or out-right parodies of) book covers, comic covers, album covers, and movie posters.
I do not take full credit for making these; many are small derivative works from some talented artists at Deviant Art, Society 6, Getty Images, and other places online. I highly recommend you visit these sites and support your favourite artists! And though I do not use these small images for any commercial purpose or financial gain, any artist who has an issue with their work being used contact me, and the noted cover(s) will be removed.
Thanks to Tom Russell for the suggestion for, and the interest in, a cover gallery.