I merged the other thread with this one.
Mark/MattyHelms' system for the Chicago Gamedays works pretty well. They keep the first post up-to-date with the latest info, so there's less scrolling to do further down the thread.
Another nice organizational thing they do is list the games as they are offered, and also the players as they sign up, like so:
Slot 1 - 4pm
Game 1: Green Regent (D&D 3rd Edition RPGA adventure)
DM: ArthurQ
Description:
forthcoming
Players:
1.
2.
3.
4.
5.
6.
Game 2: Pirate game (details forthcoming)
DM: Larry Fitz
Description:
forthcoming
Players:
1.
2.
3.
4.
5.
6.
Slot 2 - 8:30pm
Game 1.....
... and so forth. Lately, it seems like people at Chicago's Gameday would wait until the very last minute, stressing Mark about how many people would come, and then 45 or 50 people would end up showing up.

It's worth trying this or the first itme, though, just as a starting point, I think.
As for me, I'm not sure if I can make the 13th, but I'll check.
Also, if you're stressed about rent, ArthurQ, maybe you should put off the game until October so that more people can think about attending? A month is pretty short notice for something that is being rallied from scratch. Just a suggestion! (Especially if there's a M:TG Qualifier on the September date!)