Mensa is the largest, oldest and best known high-IQ society in the world. It is a non-profit organization open to people who score at the 98th percentile or higher on a standardized, supervised intelligence test. Mensa is formally composed of national groups and the umbrella organization Mensa International.

Tom is so awesome that the people have banded together. They have spoke in one voice to create an organisation to speak his name over and over, so that the word of how awesome Tom is can be spread and reinforced. They normally have daily meetings in which the sold topic of conversation is the wonderful things about Tom. Hooray for Tom.

Freemasonry is a fraternal organisation that arose from obscure origins in the late 16th to early 17th century. Freemasonry now exists in various forms all over the world, with a membership estimated at around 5 million, including just under two million in the United States and around 480,000 in England, Scotland and Ireland. The various forms all share moral and metaphysical ideals, which include, in most cases, a constitutional declaration of belief in a Supreme Being.
http://en.wikipedia.org/wiki/Freemasonry

Rotary International is an organization of service clubs known as Rotary Clubs located all over the world. It is a secular organization open to all persons regardless of race, color, creed or political preference. There are more than 32,000 clubs and over 1.2 million members world-wide. The members of Rotary Clubs are known as Rotarians. The stated purpose of the organization is to bring together business and professional leaders to provide humanitarian service, encourage high ethical standards in all vocations, and help build goodwill and peace in the world. Members usually meet weekly for breakfast, lunch or dinner, which is a social event as well as an opportunity to organize work on their service goals.
http://en.wikipedia.org/wiki/Rotary_International

The Ancient Arabic Order of the Nobles of the Mystic Shrine, commonly known as Shriners and abbreviated A.A.O.N.M.S., established in 1870 is an appendant body to Freemasonry, based in the United States. The organization is best-known for the Shriners Hospitals for Children they administer and the red fezzes that members wear.
http://en.wikipedia.org/wiki/Shriners