Good idea, but I'm not sure if it can be worked into an rss feed, and if not it'll be tricky to implement. I plan on asking a more tech-savvy friend about it later tonight, though.

I would say that the whole thing, setting up the server, RSS feeds, and some basic statistics gathering, excluding the database of horoscopes themselves, is a one- or two-weekend project for a reasonably experienced web programmer. Javascript and forms won't work in all RSS readers, but links will. So an entry in the RSS feed would look like this:

Today's horoscope: You will notice a place you ought to visit today

Yesterday's horoscope was: You will start a conversation with a stranger today
This horoscope was: untrue unhelpful true awesome

And you do some server-side magic at the destination to gather stats about who clicks on which links, filter out duplicates, and decide what to put in the feed next.