A Day Without a Mexican contains, quite possibly, the most unique and effective employment of a fantasy element I've ever seen.
While I'm not sure how much impact this film has on people who aren't from, or at least very familiar with, life in California, I think it speaks massive volumes all while maintaining a very witty and fun sense of humor about itself. While it gets over-dramatically silly, it is SPOT ON about the capability of Californian behavior (and I say that as a third generation Southern Californian who was raised, in part, by a German/Mexican stepmother).
I've noticed complaints about bad acting and/or writing in this film. The writing itself is strong, the dialogue is funny, and the cultural jokes are bordering on perfection. The acting did leave room for improvement, but that's standard in independent films that boast such a major societal commentary.
This is not the kind of film that's going to mean everything to everyone. It's geared toward a specific audience, which seems to include me, as I quite enjoyed this picture.
If you want a movie that'll, at the very least, raise some discussion, check it out.