Change Wordpress background depending on time of day

We have a site that we want the background to change depending on the time of day. For example, a sunrise background image from 5-9am then a day background from 9-5 pm and then a night background. We would like you to design it so that we can easily add different time periods and pictures if we want. Below is a post that may help you: [login to view URL] Not only would we like to change the background but we would also like to some text on the menu change depending on the time of day also. And last but not least we would like to use these plugins to have a greeting depending on the time of day such as "good morning", "good afternoon" "good evening" : [login to view URL] [login to view URL] Also, our theme that we are using: [login to view URL]