Asilomar is a state-run recreational facility on the California coast, where for many years (from the 1960s through the 1990s) there was an annual Mensa event which was the forerunner of Regional Gatherings, though there is some terminology dispute over whether Asilomar itself should be considered an RG. Unlike normal RGs, Asilomar was not affiliated with any specific local group. The Asilomar gatherings were very popular, and always sold out their limited attendance slots (the registration fee included on-site accommodations, so the number was limited by the number of rooms in the facility).
Mensa Asilomar had a reputation for hedonistic activity, and was strictly limited to attendees over 18 years old. Ultimately, the antics of Mensans apparently proved too much for the management of Asilomar to take, and they stopped allowing Mensa to use the facility, ending the long tradition.
There have been abortive attempts to start similar gatherings elsewhere, under titles such as "Son of Asilomar", but they have not been successful.