The event website provides the following history:
On a chilly Tuesday night on Halloween of 2006 Seattle launched its inaugural Seattle event at Green Lake Park. We had a great time and had a very strong event, setting a new record for an innagural run with seven participants (previous record was three people set by Denver in 2005, according to Naked Pumpkin Run Central in Boulder, Colorado). We decided to meet at 9:28 PM(or 8:88 as Josh would say) at a the secret North Seattle location disclosed to NPR Seattle participants.
This location was at the Green Lake Park East Beach, at the lifeguard elevated chair, inside of the 2.8 mile inner walk/bike trail, and adjacent to/just west of the Community Center/Evans Pool (7201 E. Green Lake Drive N). We took a few pictures clothed and naked as a group (thanks to Peterman and his friend) and then we went off!
We ran somewhere between 15-25 minutes around on the inner path and later started running along the street, before returning to the start area, posing in front of the pool/community center, and posing on the lifeguard chair. It was quite dark in the park, and there were few people on the path, and surprisingly few out driving on the streets. People were honking, pulling over and screaming, giving us cheers, people in the community center were taking our picture with their mobile phone cameras, it was awesome!