I definitely don't want to do a winner takes all. If we did a buy in, it would simply be 10 bucks, and whoever reaches the goal divides the money in the end, that way we can still stay motivated. I was thinking a goal of 5 lbs a month the next 4 months, and no gaining weight in December. If you achieve all those goals you pass, otherwise you are out.

Question is, should it be each month you need to lose 5 lbs, or if you lose more in month 1, do you get some leeway in month 2 (eg lose 8 lbs in August, you only need to lose 2 in October, or if you lose 25 lbs by Dec. 1, you can gain 5 lbs in Dec and still achieve the goal).

Thoughts?