A discussion of how board games might be more fun/easier to play if we actually played them by the rules led us to a discussion of Monopoly, a game famous for its "house rules." This evolved further into us plumbing our memories to identify which streets were represented by which colors.
We did okay with purple (Baltic and Mediterranean) and red (Kentucky, Indiana, and Illinois) but light blue had us all stumped. Scroll down for a board layout with the colors and property names.
Lots of other interesting stuff there, too, but keep in mind that it is a Wiki.