Six episodes in with 'Castle' and we can see now that Detective Kate Beckett is working out of the 12th Precinct. (It was embossed on the elevator doors in "Always Buy Retail".) Most famously, the 12th was the home of 'Barney Miller' and his squad of detectives, but that original building is now home to the Theodore Roosevelt Police Commissioner Museum. So they had to move to new digs, which is where we now find Rick Castle getting his inspirations. The 12th Precinct has also shown up in the "Monster" episode of 'Law & Order: Criminal Intent'. Robert Goren and Alexandra Eames dropped by there while they were investigating the death of Laura Dietrich. (Hopefully no relation to Detective Arthur Dietrich of 'Barney Miller', but then again - it is a small world.) I don't know which 'CSI: NY' episode it was for, but last November this building in Los Angeles was dressed up to look like the exterior of the 12th Precinct.
With connections to both the 'Law & Order' and 'CSI' franchises, 'Castle' is deeply imbedded into Toobworld. But then, it already was when they used the New York Ledger as their official newspaper.....