diaspora (n.) - the dispersion or spreading of something that was originally localized (as a people or language or culture)
Name, and tell me a little about, your favorite diasporas from history and fiction.
A historical diaspora might be a well-documented one such as the Jewish diaspora or hypothesized one such as the Austronesian dispersal. A fictional diaspora can be any non-factual scattering of races, planetary inhabitants, etc. that you like.
My favorite historical diaspora would probably be that of Chinese-Americans, though I'm fascinated as well by the history of Perenakans (Straits Chinese) such as yodge, and of Chinese abroad.
My pet fictional diasporas are a toss-up between the hegira of Dan Simmons's Hyperion/Endymion universe and the "depleted Earth" migration of Firefly that led to the colonization of the Alliance worlds. A close runner-up is the Gaea/Keeper-induced diaspora of Orson Scott Card's Homecoming series (which is itself a retelling of the Book of Mormon).
In other news: Here's Dubya, Trasky Dubya, courtesy of flemco of Two Lumps fame.