I'm looking for a script (preferably php) that will let me list a number of tasks, and then let people place bids on when they think a set action will occur on a particular task (expiry date mainly). So, person A thinks that task X will end on week 12 and puts a $10 bid on that date, person B thinks it will end on week 9 and does the same. The closest person / people to the correct date when the task actually expires will then take winning prizes (possibly 2nd and 3rd prizes too). Can anyone tell me what could accomplish this (either opensource or paid, I don't care, but obviously I appreciate good value) with minimal effort on my part. I don't feel like starting another project from scratch right now! Thanks in advance!