For those cachers around and caching in August 2013 there was the opportunity to get one for each day that they cached (BARGAIN). Recently there had been the "7 Souvenirs of August", which related to Types of caches found in August. (SORRY, but those ones won't count for this Challenge)
This Challenge requires the finder to have in their profile a collection of (at least) 7 souvenirs that are totally DATE RELATED (and not month related). That means that they were added because of the date required, as in the International CITO Day, or with the October 12, 2014 International EarthCache Day where finding an EarthCache is required on that date. Souvenirs added because you cached in different states don't count for this Challenge (they do for GC5AKTV in Sydney, or GC5AH4V in Darwin). There are many reasons, and the above mentioned ones are not exhaustive.
Have you already completed the requirements for this Challenge, GREAT, then you are on your way to bigger ones.
See the sample below. (Thanks, and apologies to Browngang)