The New York Times now has a remarkable interactive set of maps of 2010 Census data regarding ethnicity that scales from the whole country down to Census tracts of a few thousand people.

For example, in the Valley Glen neighborhood in the center of the San Fernando Valley, I was struck a few years ago by the unbelievably elaborate security fences with lethal finials that were being built around typical little SFV post-War tract houses. How can Mexicans afford them, I wondered. On a second visit, it dawned on me that the people turning their homes into fortified bunkers weren't mostly Mexican, they were Armenians and / or other newcomers, newly arrived from the ex-Soviet Union or West Asia. Sure enough, you can see on the highest resolution map that, say, Census tract 123304 has seen its white population increase by 77% over the last ten years, while its Hispanic population fell by 1 percent. The classiness of the get-away cars in Valley Glen gang shootings has increased correspondingly over the last decade, with Beemers and Lexi now favored.
By hitting View More Maps, you can see each map in 12 different flavors of information conveyed.