Welcome to the Northern California version of "The Jasmer Challenge". You must have logged at least one cache that was placed in every month back to the start of Geocaching (May 2000).
In order to log this cache, you need to provide the GC code of a cache that was placed in each month for all of 2000 and 2001 in your log entry. Of course, you have to have a find for caches placed in all other months (up to and including the current month) as well, but those tend to be easier to come by and don't require as much verification. You are also encouraged to run the MonthlyCoverage GSAK macro that sums this all up and post a screen grab of the output in the Gallery.
Here is an example of my progress towards logging this cache:
I also encourage others to create similar "Jasmer Challenge" caches in their own state. (No more than one per major metropolitan area please.)