I could do that, but I need to have the order correct. Someone who brought a visitor last week should be lower in the list than someone who brought someone two weeks ago, who should then be lower than someone who hasn't brought one in a month.

I'm trying to think over a couple ways to do this, but I just can't think out the algorithm. I have to figure that it's good that I need a big table already, where I'll have all the members on one axis and all the weeks on another axis, and the cells will all be filled with the number of visitors they brought that week. I'm just not sure how to use that data to create a sorted list in the manner in which I'm trying.