Are you making any money from AdSense? If not, would you consider taking it off and using the real estate for something else?
AdSense, if it isn't making money, is at least amusing. I like to see what Google thinks is relevant to a site. On your site "Wilder Coast" apparently makes AdSense believe that books by Laura Ingals Wilder should be of interest to your readers.
Really, if you (and everyone else out there) aren't making some serious money from Google with you AdSense space, why do you have it?