Halloween at an Amusement Park?

Have any of you gone to any of the big amusement parks' Halloween events?  I know that many of the big parks in the north are open during October even though it is cold so that people can enjoy Halloween-themed events.  I have never been but I am really looking forward to going someday.   This link is to Six Flags in New Jersey, but I think all Six Flags do something for Halloween.