Okay, I'll admit that our son has been trick-or-treating before. It was last year, when he was about 20 months old. So, does it count? By my estimation, no. In fact, I bet his third year of trick-or-treating will feel a lot like the "first-ever." That's one of the cool things about being a little kid: For the first few years of life, everything seems brand new and warrants an unabashed sense of wonder, even if you've actually done whatever it is that's so amazing before. Because your memory span is not much longer than that of a goldfish. 

And, in my mind, that's a pretty cool thing. 

TDT: Do you know what Halloween is? 
Son: Yeah. I know what Halloween is.
TDT: So...what is it? 
Son: Girls wear butterfly wings and boys wear chicken hats. 
TDT: Oh, yeah? 
Son: Yeah. My chicken hat is asleep over there. *points*
TDT: In your toy box? 
Son: Yeah. Chicken hat sleeping in toy box. 
TDT: So, hey. Do you know what trick-or-treating is? 
Son: *silence*
TDT: Remember? It's that thing where you knock on the door or push the button (this is how he understands ringing a doorbell) and when someone answers you shout, "Trick or treat!" And then that person puts some candy in your trick-or-treat bag. 
Son: Treat???
TDT: Yeah, treat!
Son: Push the button, I get treat!!!!11!! *excited laughter commences*
TDT: You have to wear a costume, though. 
Son: *silence*
TDT: But that's OK, because you have one. 
Son: Yeah. I have costooome.
TDT: Do you know what you're gonna be for Halloween? 
Son: Chicken hat. 
TDT: Actually, Daddy and I found a root beer costume for you. 
Son: I have root beers???
TDT: No, not the drink. It's a root beer <em>costume</em>.
Son: Go get root beers now???
TDT: I have a feeling that this interview is over now.
Son: Get in car, get root beers now!!! 