In Mensa parlance, an RG is a Regional Gathering. Such gatherings are planned and hosted by a local Mensa group. There are many variations on the RG idea (e.g. mini RG, outdoor RG) but the typical type is held over a weekend at a hotel. They are usually held Friday afternoon or evening to Sunday morning or afternoon, though some groups have their RG over a holiday weekend, starting a day earlier or ending a day later. The number of attendees vary, with 100 – 150 being typical, but with a range of three dozen to over 500! Attendees are a mixture of members of the sponsoring group and Mensans who travel, sometimes great distances, to attend the RG. Guests of members are also welcome. People can register for a single day or the whole weekend. The hosting hotel often has a special room rate for RG attendees. Staying on site is of course not required (though you might miss some of the fun.)
The RG schedule includes a variety of activities and events for the enjoyment of Mensans. These include games, tournaments, crafts, contests, and speakers, both serious and frivolous. There is usually more than one thing going on at a time, so attendees have a choice of how to spend their time. Some people just like to chat or play games. There are usually one or more major events, such as a dance or variety show. Fund raising for the local group’s scholarship fund is not unusual.
Snacks and refreshments are available in a hospitality suite. Some meals are often (but not always) included in the registration price.
Overall the event is an opportunity to meet and socialize with other Mensans. You can have your brain stimulated as little or as much as you’d like. RGs are popular because they are designed to be fun and interesting for Mensans.