OK, here's what I know about Guy Fawkes Day: Kids start preparing for it a week or so before the actual day. Usually a few preteen kids working together will first build a "guy" - a dummy made from old clothes stuffed with rags or crumpled newspaper. They usually put him in a wheelbarrow, or nowadays tie him to a plastic lawn chair, to make him easily portable. Usually on the Saturday before GF Day, they will set him up in a public place, anywhere there is a lot of foot traffic, and accost passersby with the words "A penny for the guy." (They don't go door to door, like American trick-or-treaters.) People are expected to give them a little money. (More than a penny, nowadays, I suspect.) The kids are supposed to use the money to buy fireworks, which they then stuff into the guy.
You will see signs posted around the neighborhood announcing that there will be a bonfire at such-and-such a place, sponsored by such-and-such an organization. That's because, in the interest of safety, it's a good idea to have this part supervised by adults. On the night of November 5, the kids bring their guys and throw them on the fire.
I haven't actually witnessed such a bonfire, but when I visited England shortly before Nov. 5, 1985, I saw several "guys."
I'm interested in hearing from Brits about their own experiences. Is Guy Fawkes Day, like American Halloween, also a time for pranks and minor vandalism? Americans often have fond memories of Halloween, because it is often their first experience of being outdoors at night in groups with no adults.