On at least three separate occasions, Addison casts a shadow. As a hologram, this would not be possible. Also, in one case, the wind also can be seen to be blowing through her hair.
(at around 30 mins) Neil maneuvers around Addison to talk to Ben face-to-face. Addison is supposed to be an incorporeal hologram that no one but Ben can see.
About 4:19, Neal, on the phone, talking about going on "The Tonight Show", says, he will "come on down" in a very specific way; but, he's imitating Bob Barker on "The Price is Right".