If you've ever wanted to create your own custom iGoogle theme, there's now an API from Google that will let you do it. As you can see in our new Themes API profile it's fairly straightforward. As "Creating your own theme isn't rocket science. If you can create a webpage, then you can create a theme. There are only three steps involved: designing images for the header and footer, entering metadata and color information in an XML file, and submitting the theme." In addition to allowing a static image, the API allows a theme to change over the course of a day in order to "reveal a visual storyline, message, or anything else."
To jumpstart development Google released an initial set of designer-created themes. Here's an example from designer Mark Frauenfelder over at Boing Boing that tells a story and changes throughout the day. You can see our Adventure in Lollipopland profile here.