Both top spots are now booked from May through November 2014.  (There is at least one top spot available from December 2014 onwards at this point.)  There is also at least one 2nd-from-the-top spot available from June onwards.  There are also, of course, 3rd from the top spots available most months as well.  Rates are here.  E-mail me at bleiter-at-uchicago-dot-edu with questions or to book ads.  Thanks.