Force “Published” date, or adding an additional Date field

Hello,

The Need
I have a series of posts labelled “Events” that show upcoming events for my school. I’d like to assign each individual post the date that the event is occurring– for instance, the event “School Dance” happens on September 26, 2008; the event “Football Game” happens on October 12, 2008; and so on…

Originally, I had just been typing these dates within the post themselves, but I’d like to start sorting these events by their “occurring date”, with the most upcoming events listed first and the later events listed after. Something like this:

Events
– School Dance / September 26, 2008
– Football Game / October 12, 2008
– Senior Breakfast / November 6, 2008

The Problem
My idea was to sort the events using the “orderby=date” and “order=DESC” tags, but in order to get the events to sort correctly I’d have to change their Published dates.

I thought I could just change the Published date of each post to reflect the date which they occur, but when I changed the date to a future date (example– changing the Published date of “School Dance” from its original published date of August 6, 2008 to September 26, 2008), the post would be removed from the listing and its status would turn to “Scheduled.”

The Question(s)
Is there a way to force change the date of a post, even to something in the future, and still have it post (as opposed to “Scheduled”)?

Alternatively, is there a better way to go about this? For example, is there a way to create an additional Date field within a post, and then have the posts sorted by that date (instead of the Published date)?

My apologies for the lengthy post– I wanted to be as clear as possible. Many thanks for any replies!

Derek