WARNING: This is a spoiler if you haven't seen the most recent episodes broadcast by NBC in North America.
In the most recent episode, both the Seinfeld's and the Costanza's are considering moving to a retirement community called Del Boca Vista. I believe that it's supposed to be in Boca Raton, Florida. Here's why:
In the one-hour episode in which Jerry's parents are ostracized by their neighbors because Jerry bought them a Cadillac, Jerry's father says that now they'll have to move to "Boca", which is the common nickname for Boca Raton.
By the way, the humor of that remark may not be apparent to people from outside New York. As a retirement destination, Boca Raton is a step up from some other places in south Florida. Nearly everyone I've met who has retired there from Brooklyn or Queens owns a Cadillac or a Lincoln. It's almost as if you need to own one in order to fit in there.
---Alvin H. Nichter