In the episode Committed if you look very closely you will notice that Jorja Fox has one fingernail painted gold. The best scene to see this is when she collected the cigarette from the ash tray after speaking to the nurse. This gold fingernail is a reference...
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Around the 53 minute mark (on TV) of the episode, when Nick and Catherine are looking at Jodi's (the sister of victim, Anne-Marie) computer, they are going through her bank statements from previous months, the computer screen scrolls down showing charges...
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During The CSI Movie, GRAVE DANGER, you will see a delivery boy being interrogated as to where he picked up the "evil" package. He gives a bogus address, and when they go to the house address given, you will see a poster on the wall in the background...
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