For what it's worth, I too had the same question about the deadline, and
certainly didn't want to make a costly mistake.  I asked several people
about the exact meaning of "midnight October 15 2004, Australian Eastern
Standard Time" as stated in the rules -- and got conflicting responses from
them.  So I looked at several dictionaries, which didn't help: one site
http://www.wordiq.com/definition/Midnight even says, "each day thus has two
midnights, one at the start and one at the end" in its definition of
"midnight"!  I then contacted the competition organizers for clarification.
 They replied that due to apparent confusion, the deadline had been
extended.
I like the suggestion of using the ISO 8601 standard and eliminating the
word "midnight".