California - SoCal- Los Angeles Angels vs. Los Angeles Dodgers
California- North- Oakland A's vs. San Fransisco Giants
Beltway Series- Baltimore Orioles vs. Washington Nationals
Although I am no longer living in Missouri, I'd like to see the I-70 series happen again, mostly so my friends who wear Cardinals jerseys while actually being Royals fans will have to choose their colors.
In case you didn't know, the other qualifiers are the Detroit Tigers and Pittsburgh Pirates.