Here goes:
All registered posters (you must post) have a number. The final day of the month, Mike tells us to pick a number between a specified range and post at midnite...the first number posted is the first Mike checks...if that isn't a valid number, he takes the second, and so on.
He announces the winner and gives them 48 or 72 hrs to respond....if not he takes the next number.
This way its random and in effect we choose the winner