The alt.pub.havens-rest reality is a shared science fictional universe centered around the titular bar, located on a nexus world surrounded by dimensional rifts. It draws in customers from many different worlds and universes. Team M.E.C.H.A. from 000SUPERGUY traveled there on their way to the Looniverse during the Grand Tour; they teamed up with the crew of the Starship Constellation (no relation), who led them to a dimension warp which ultimately brought them to the RoboMACs Exodus universe.
For more information, see Team M.E.C.H.A. author Chris Meadows's retrospective on the alt.pub.* groups.