Funny you should say that...
I've been thinking about doing something like that for the next season. It wouldn't be betting, though; it would just be a fun contest, and I'm thinking about having a prize available for the winner.
The idea that I've had would be like this...
Everyone would PM me who they think would win during a week in the season. For example,...
Ravens over Colts, Lions over Vikings, Texans over Browns, etc.
I'd keep track of these, and count how many each individual got right. The person who gets the most, wins 3 points for the week, 2nd place gets 2 and 3rd place gets 1.
At the end of the season, the top three or so people would "go on" to the playoffs, where we would use the same (or a similar) system that we used here this month. The regular season totals go away; they mean nothing at this point.
Whadya think?