The 12:12:12 souvenir commemorates the last calendar alignment this century. The 12-12-12 souvenir was awarded to anyone who logged an “Attended” for an Event Cache or a “Found it” on another cache type on December 12, 2012.

12th December 2012 – 12.12.12 Few Drinks GC41E75 – cache #2254
In order for people to have this souvenir a cache event was arranged by Goldfish58 at the Squinting Cat pub in Harrogate, there were a couple of dozen or so cachers in attendance, though I only could stay for an hour as I had to be elsewhere later in the evening