We also had 30+ cachers at the GC4NHVD event near Pittsburgh, even though we had intermittent drizzle all morning before the event. (Not a drop during the event, luckily!!)
There is an EarthCache in the park where we had the event and several attendees made this their first EC ever. One commented that she very much appreciated the explanation of ECs given at the event, since she was not real familiar with them. She also suggested that I make sure to have a link to the EarthCache.com website on all my ECs, and I do believe I will make sure I've done that. Looks like learning still goes both ways!!