My idea with arguing in pairs, what that the pair would argue against each other, ie pro- and against something specific, or argue two different standpoints in the same issue. Is that what you mean two, Sleepo?
If we it do this way, Sleep comes up with debate topics and he (perhaps together with one or more other independant persons) decides the pairings and the results. The topics we debate should not be within the area of our expertise since that is unfair - (with the possible exception of a HLD and Georgi pairing, since I believe they both have degrees in history). I think it would be more fun if we argued for things which aren't our real opinions, it is more challenging that way.
I am a little big against Frogus and Sleep regarding the "cup" format, since that means a person who looses the first debate is then out until or if we start a new series of debates. I am more for a series format where all meet all - if we want to crown a winner, we can count points instead, for instance like in football: 3 for victory, 1 for draw, 0 for loss.
A preset number of post and words will be necessary, otherwise the debates will go on forever
A question: are we playing clean or dirty, ie should we argue correctly and follow the rules of true debate, or can we use rethorics and logical fallacies?
A helpful link regarding what is a valid argument and not:
http://www.infidels.org/news/atheism/logic.html
Please don't pay any attention to the fact that the list is made by an atheistic orginasation, the classification in the same as is generally used in logics and debate concerning any topic. If somebody really doubts the reliability of this list, I can dig up another at some other site (the philosophy.net probably has one).