The event was the Avalon Music Festival at the Avalon Resort, a clothing optional resort in Paw Paw, WV. I don't remember when it started or if it is still being held, but for many years it was an annual event. During it's early years, some members of the DC area folk music community did the booking for the event, so many of the performers were very familiar to DC area folk fans. In addition to the Limeliters, many other performers participated in the festival, including Modern Man (David Buskin, Rob Carlson and George Wurzbach). They used their experience as inspiration for their song "Folk Music in the Nude."