I asked my neighbors for the name of the trees that are currently putting out white flowers around Leisure World. I received several suggestions, including:
Orchid tree: http://en.wikipedia.org/wiki/Phanera_variegata
Desert willow: http://en.wikipedia.org/wiki/Chilopsis
Callery pear: http://en.wikipedia.org/wiki/Pyrus_calleryana
, but nobody knew for sure, so I finally decided to get serious, and take a photo, which I sent to Moon Valley Nurseries. They said it was a Pyrus kawakamii, or Evergreen pear. and That's when I found this article, which has some beautiful photos.