A play by e-mail role-playing game played by Garry Stahl and Jay P. Hailey. It is set in the Epiphany Trek continuity and is canon to Epiphany Trek.
Being that many elements of Star Trek: Outwardly Mobile were pulled into his game, Garry wanted to play with Jay's characters, it is responsible for most of the cross overs in the two fan series. However, they are not set in the same continuity, they just share some elements. While characters, places and ships are shared, often the fates and events of said characters and ships are extremely different.
The Starbase 600 game has been running since 1998 and shows no sign of stopping.