The original plan was weigh in on Monday every week, and then the person with the least % of body weight lost had to chip in $5 (starting in January) and at the end of the challenge the person with the overall most % of body weight lost would get the total.
That being said, if we decide to not do the money thing, it doesn't really matter how often/when we weigh in (and even if we do, it certainly doesn't matter until January).
If we do keep the money thing, we'd want to maybe still to 1/week to keep everyone on the same page.
Also, we could switch to an "everyone wins" style challenge where the goal is to loose X number of pounds. Right now it's more of a "The Biggest Looser" type challenge.
I think the money idea is still a good one - so I'd personally like to see us stick to that. Ok, for now I'll just weigh in whenever I do it and then I'll mark it down, but come January I'll only do a weigh in on Mondays.