I enabled a new front page feature which loads a new guest in the "guests" box on the front page automatically. It switches every time the page is re-cached on the server, which means that it won't show a new guest every time you hit the 'refresh'. For that reason, I included a little '...see more guests' link below the featured guest box. When you click that, it will show a new one. Otherwise, I think it will show a new one when you re-open your browser and/or when a little time has passed (hard to get a straight answer on this from the documentation.)
Anyway, just another way to make our pages a little more dynamic. If we like this, we can enable it for the "recent questions" and "featured hosts" boxes too.
To swap a one guest profile out for another one (I grabbed the ones that are here now more or less randomly), copy the guest's intro box template from the Teahouse/Guests page, go to one of the pages below, and paste that template over the guest template that's already there.