Miguel Ferrer was so devoted to his role, he refused to take time off, even when diagnosed with cancer. When it started to affect his voice, his illness was written into the character as well.
LL Cool J tried to perform his own stunts, where possible. He explained: "I want people to know that I'm invested in the character and I want to give them the real experience".
Here's the boat shed's co-ordinates - "33.974828,-118.446349". Punch them into google maps for a look.
Chris O'Donnell had expressed interest in having Michael Weatherly appear on the show. This finally occurred in Blame It on Rio (2015), although the characters did not acknowledge that they knew each other.
When Dominic Vail (Adam Jamal Craig) was written out of the show, a main cast position was offered to Brian Avers (Special Agent Mike Renko), who also appeared in the backdoor pilot on NCIS (2003). Avers turned down the contract but remained a recurring role. As a result, the popular character of Marty Deeks (Eric Christian Olsen) was created.