The Intertemporal Association of Time Travellers
The Intertemporal Association of Time Travellers (IATT) is the pan-dimensional group devoted to fostering trust and cooperation between timelines. They were founded in 4.5 billion B.C., when anonymous traveled back in time and sneezed in the primordial soup, creating life. Technically, since anyone who has ever lived has traveled to the future, everyone is a member, and as such obtains infinite power, the ability to change history, and a free croissant at the meeting every Wednesday. Time Travellers like to heckle non-time travelers for never having made out with Mary Magdalene.
Goals and Guidelines
The IATT's stated goals are to "kind of travel around, I guess," although several books of guidelines are known to exist (such as The Time Traveler's Guide of Who Not to Kill or Sleep With). The association itself has very few rules, although there are several bylaws governing calling shotgun and the Not-It game. For some reason Oscar Wilde, no surprise there, is currently the association's president, known as His Wildeness, Grand Overlord of Tyme.
Since a prerequisite to using membership benefits is a knowledge that the association exists, active members are typically either time travelers, historical figures (no matter how minor), and anyone who has "fallen in love" with a time traveler who has "lost their phone number". The Authorized Personnel Only sections of Wal-Marts are often time traveler meetings in disguise, so just go right in and get your free pastry.
Typical activities in IATT meetings include rousing games of capture the flag and discussing which historical personages members have snogged. They also enjoy long discussions about future events that never really happened, but most other travelers are too lazy to investigate. Sometimes members travel back in time, just to have their pictures taken at historic events like the Kennedy Assassination, 9/11, World War II, The Great Depression, or even the founding of Microsoft.
Members must not go back in time to change history, like to prevent the election of Al Gore in November 2000, or prevent the assassination of Jimmy Carter in 1975, or stop John Lennon from bringing the Beatles back together by getting some Crazed Fan to shoot him or something. Also no pretending to be the voice of God for Joan of Arc or Moses or any other non-religious figure to prevent Atheism from becoming the dominate way of life on planet Mongo, which would change the name to Earth instead and bring about events time travelers don't want to happen, like The Crusades, The Inquisition, and the discovery of soy.