Well, I don't think it would mean you need to change the site. When you install the plugin, you just go to the posts that have to do with whatever Event you're discussing and add the relevant dates and times. You can then set it to display a list of upcoming events by date, as well as have a calendar which displays said info (and links to the informational post).
If it starts this weekend, I'd say this would be the quickest solution for you to use. you may not get the post to "stick" at the top of the index page, but you can add the information where it's readily seen in a snap.