I used to spend a week in Mexico City every summer at the big Star Wars convention but haven't the last two years; it was pretty much total emersion and I'd come home close to fluent before it wore off after a few months. Not to mention running into "real" Spaniards and getting a totally different dialect.

And the spanish I get to use in So Cal is lazy ass spanglish and sucks given the spanish speaking populace. Just "peasant" espanol.