Diogenes Club

Mycroft Holmes (right), co-founder of the Diogenes Club (depicted here in 221B Baker Street), illustrated by Sidney Paget

The Diogenes Club is a fictional gentlemen's club created by Sir Arthur Conan Doyle and featured in several Sherlock Holmes stories, such as 1893's "The Adventure of the Greek Interpreter". It seems to have been named after Diogenes the Cynic (though this is never explained in the original stories) and was co-founded by Sherlock's indolent elder brother Mycroft Holmes.

The club as described by Sherlock Holmes in "The Adventure of the Greek Interpreter":

"There are many men in London, you know, who, some from shyness, some from misanthropy, have no wish for the company of their fellows. Yet they are not averse to comfortable chairs and the latest periodicals. It is for the convenience of these that the Diogenes Club was started, and it now contains the most unsociable and unclubbable men in town. No member is permitted to take the least notice of any other one. Save in the Stranger's Room, no talking is, under any circumstances, allowed, and three offences, if brought to the notice of the committee, render the talker liable to expulsion. My brother was one of the founders, and I have myself found it a very soothing atmosphere."