Currently there is a possibility to acquire a quadruple Jasmer. The limitation is August 2000 as only 4 exist in the world: 3 in the United States and another in Sweden. I have completed a quad Jasmer but now I'm curious as to who else is part of this club? This request would certainly answer my question.
See this Official Geocaching Blog post about The Jasmer Challenge and the remaining 4 August 2000 caches.