When: 19:00 until 20:00 or everyone has left.
Where: Robin's Donuts, 4555 Rochedale Blvd for those who do not want to use their gps
All are invited to celebrate Dönerstag and earn a souvenir.
Dönerstag is German for Thursday.
Apparently Signal the geocaching HQ mascot will be touring Germany this April.
So bring your stories, your questions and whatever else you fell like bringing. 
For more about souvenirs visit The Geocaching Blog