globetrotters.us:I had two thoughts on an approach.
1) Make a photo goal with take a picture of a trivia board with your name on it (on a specific date?).
2) Make a Geocaching event at my Local BW3, and call it a joint Geocaching Waymarking Meet and Greet, and open it up to anyone who is playing the trivia at the same time, anywhere.
The main problem is that with the different time zones, picking a good time would be difficult. My thought that 9PM EST on a Tuesday, Wednesday or Thursday would be best, so there wouldn't be big crowds at the establishment we chose. The second is I'm not sure about getting it approved because of the commercial rules? Can someone comment on that?
Wait, let me put on my volunteer geocaching reviewer hat. (really, if you don't know... I am one)
In my opinion as a reviewer, I don't see any issue with this idea as presented so far. Events are often held at a named restaurant and if there is a community building activity during the event in addition to the meet-and-greet then that is fine. Playing trivia is free isn't it?
BQ hat back on...
In Geocaching, there are flash mobs already. This seems to be at least equivalent if not better since the event would last longer and be more social. Here's how I would see this working:
A date is picked and a time (I like 9pm EST too). Any interested Waymarker creates an Event Cache listing on Geocaching.com and includes a paragraph similar to this:
"This is a simulcast event being hosted by several Waymarkers around the world and is open to any Geocachers as well. As part of the event, we will be challenging other locations to a trivia match using the Buzzword trivia service at the restaurant. Come help us rack up a high score and show those other locations how smart we are! We will take a group photo with our score for use in the Photo Goals category."
There would have to be normal event content as well. I think this could be great fun and a great way to introduce the local cachers to Waymarking since it would offer a way to ease them into discussions in a comfortable social setting.

BQ
p.s. I think my paragraph needs a lot of work/editing.