I bought more candy than I needed with the intention of taking any leftover candy to the office for candy dishes and treats for the kids our agency serves. It's a good thing I did, because we had a Halloween surprise that led to tons of trick-or-treaters.
We've lived in this neighborhood just over a year, but we didn't spend Halloween night at home- we went to my brother-in-law's place and let all the kids trick-or-treat there. It's no wonder that I was so surprised to see what happens in my neighborhood every year.
We live in the middle of a block, and on the other side of the street, down on the corner, is a big field where all the kids play football and frisbee and stuff like that. Just before 5pm, I ran to the take-and-bake pizza place to get our dinner, and when I turned back onto our street just after 5pm, *POOF* a big Halloween carnival had appeared in the field on the corner. 5 moonwalks, a stage for the live band (yep, live band), and tables/coolers/grills. As it turns out, a local church takes over the field every year with permission from the homeowner's association and has the carnival. Costume contest, free hot dogs/chips/drinks, goody bags for everybody, and the live band. The entire neighborhood came out, as did the neighborhood down the street.
So I couldn't tell you a number, but based on how much candy I bought and how many kids I saw, we had to've had at least 150. I had six huge bags of candy and ran out of all but a couple of handfuls of mini Tootsie Rolls.
On a side note, my 6th grader thought to trick-or-treat for canned goods for his school's food drive, which ended yesterday. I helped him carry 6 bags of groceries into his homeroom, and that was from just one full block. I had to pat him on the back for his idea.