Historical

Omerta
Massive multiplayer text-based roleplaying game about gangsters and the Mafia.
http://www.barafranca.com/

Pan Historia
A role play site for interactive creative fiction writing. Free basic membership for all genres. Instant messaging, home pages.
http://www.panhistoria.com

The Roman Online Gaming Society
Group dedicated to gaming including roleplaying based on a Roman theme.
http://www.romanlegion.com/