As of today (9-25-14) there are four possible world-series matchups of teams who're close neighbors:

1) Dodgers-Angels
2) Oakland-SF
3) St. Louis-Kansas City
4) Washington-Baltimore

Trivia question: What was the last world Series where all games were played in the same stadium?

Answer: The 1944 WS when the St. Louis Cardinals beat the St. Louis Browns (now the Baltimore O's, as of 1954) in six games. That series played an important role in World War II. During the Battle of the Bulge in December 1944, the Germans infiltrated U.S. lines with English-speakers who posed as Americans, giving confusing orders and wrong directions to US troops. The Americans produced a set of questions to expose the imposters.

One of the questions was about the 1944 World Series. It was the Browns' only World Series in their history, and the question stumped the German imposters.