The Cast Showoff:Several actors have had the chance to show off skills on-screen. Sinise appeared with his Lt.Dan Band in "Stuck On You". In "Tri-Borough", there's a scene at an art gallery. Flack makes a remark about the paintings not selling well, and Danny says "yeah I can see why" while nodding his head toward one of the paintings. The one he's indicating was actually made by the actor who plays Danny, Carmine Giovinazzo. He also has a band, Cesau, but it hasn't appeared on the show as yet. Also, Danny's aborted baseball career was based on Carmine's own injury-aborted baseball dreams, and there was one ep where he showed off his pitching ability. Also, Danny's tattoo is the actor's real one. Several episodes also have Melina Kanakaredes showing off her knowledge of fluent Greek. (her parents are Greek immigrants and she and her family often visit the country).
Comically Missing the Point: after Mac let the tickets he was to have used with Claire go into the ocean in "Indelible", a few fans complained he was littering and thus breaking the law. (Technically true, but it was still a poignant scene)
The episode "All Access" had a website tie-in. Stella's psycho boyfriend used the website aresanob.com, and an ad at the end of the ep told viewers to visit the site to see what Stella saw. This was also the opening page of the site "Click here to see what Stella saw". The content after the click was the sex tape Frankie posted online and then an extended promo for the ep. (if you're hoping to check it out now, it's long gone, you'll get redirected to the CBS website.)
Stella's HIV scare was a project in collaboration with the website knowhivaids.org
You Look Familiar: Carmine Giovinazzo (Danny) and A.J.Buckley (Adam) appeared on CSI: Crime Scene Investigation before becoming CSI NY regulars. Carmine's was a brief guest appearance, as a minor character, and A.J. was the killer in his ep. Also, Alex Carter, Detctive Vartaan on the original series, was in one ep of this show.
The season 9 finale "Today Is Life" was based on a real life incident in The Seventies when a cop shot an unarmed man and a mob really did try to storm the precinct.
Mac reveals in season 9 that he can't recall the events leading up to his being shot, a type of amnesia that isn't uncommon in trauma patients. A few months after filming the season 8 finale, Gary Sinise suffered a similar memory loss to Mac's, minus the lingering speech aphasia, after being involved in a car accident that fortunately didn't severely injure him, but left him with a rather nasty concussion, along with a lot of bumps and bruises.
An actual dead body was found in one of the buildings used for filming, but it wasn't a murder case, rather, it was a long-dead tenant who got overlooked somehow. It bore similarities to the episode "Not What It Looks Like", but without the homicide aspect.
Lindsay Monroe/Messer's birthplace is possibly a left-over portion of the backstory of Catherine Willows from the original CSI: Crime Scene Investigation. For a time, the official character bios on CBS's website listed Catherine as being from Bozeman, Montana, but that was scrapped sometime before the finalized version of her backstory was revealed onscreen.
What Could Have Been: After the show ended, one of the producers revealed there had been talk of hooking Mac up with Jo at the end. They thought about having him propose to her instead of Christine, and though they definitely wanted a wedding if they made 200 episodes, they weren't sure if Mac would marry Christine or if they'd do a fake out and reveal him to be marrying Jo instead. One does reason, though, that some events of season 9 might have been written differently if they'd gone with one of these. Alternately, they might've somehow written out Christine and had Mac and Jo pair up later on, if they'd had more seasons. Mild Internet Backdraft has been generated by at least these things (particularly the idea of attempts to pair him up with Jo by ep 200, which would have only been three eps after the finale, if season 9 stayed as it was written).
Christine was originally conceived as someone Mac knew from his military days, but the writers probably realized it would have created a continuity problem with Mac's timeline since they still would have used the same character age for her that they did in the final scenario.
Also see Aborted Arc on the main page for info on the scrapped Mac/Aubrey/Peyton love triangle in season 6-7.
Everyone was to have had a day off episode, but Mac,Danny(who was to have his own along with the one of Lindsay's own despite their marriage),Hawkes and Sid never got one, perhaps due to the compressed season or a desire to do a crossover in hopes of boosting ratings at the last minute.Spoilers said Mac's would involve him taking a day off at Christine's urging, then getting stuck on a broken subway. It was announced as episode 15, but this episode later became the second half of the crossover with CSI: Crime Scene Investigation.
Andy Garcia and Ray Liotta were offered the mac role,but turned it down. The character was named Rick Castelluci at that time; Gary Sinise comvinced them to change it after taking the part.
Anthony Zuiker wanted "Behind Blue Eyes" as the show theme.
Accidentally Accurate: Although the novels weren't true canon and some bits got invalidated by by later episodes, one of them got a tidbit right, having Mac recall that Claire liked opera. 'Indelible' reveals they were planning to go to one on 9/11 and Mac kept the tickets until the 10th anniversary.
Although Christine's brother was Stan Whitney, that was apparently also the name of a minor character in "Charge of This Post" in season two. Despite the military backstory originally planned, there's no evidence he(the soldier who dies in Mac's arms in flashback) was going to be her brother.