I read about this on Neil Gaiman's blog. He wasn't too sure if it was true or just a myth but I really hope it is real.
Apparently back when Margaret Thatcher was PM of England, there was a secret plan to promote halloween because studies showed that regions where people celebrate halloween had less celebration of Guy Fawkes day (4th of November) and thus less fireworks related injuries.
Check this out if you want to see some cool-looking pumpkins
http://www.phrenopolis.com/pumpkins/index.html. I bookmarked it a while ago and I've lost track of who's website it actually is - there's remarkably little personal information. I think it's the website of Dave Grossman, who has done a lot of gaming related stuff including cowriting Monkey Island (I'm not sure which one).