This website has a full history of the holiday we know as Halloween. You can read how the holiday stemmed from a Celtic festival, known as Samhain, to a Catholic holy day, known as All Saint's Day, to the holiday we celebrate today, known as Halloween. There is also a page for pumpkin carving templates.
If you still don't have an idea of what your Halloween costume will be this year, and money is an issue, then go to this article on ABC News for a few last-minute costume ideas.
You can find a list of free printables, crafts and recipes for kids on this website.
This is another list of crafts and recipes that are fun for the whole family to enjoy.