Now before you go ahead and spam VIDEO GAMES FORUM on my ass hear me out.
The general problem with organizing communal events such as these is advertising, I've made a couple tournaments in the past, some have happened, some haven't (namely the bigger ones). It would be extremely implausible to suggest that all the people who would be interested lurk the Video games forum day and night but I know that a large number of users lurk the General forum more regularly, just out of general experience. Hell its funnier and more interesting most of the time.
I would bet that at least two people on the general forum, who don't visit video games, have played AOE3, and are interested in this sort of thing.
And there we have it, if your interested in competing in a friendly AOE3 tournament with potential prizes click my signature link, post your name and all is explained.
Good luck to everybody competing! I hope this goes through. A large tournament would be excellent but I would be settled with 8 or 16 players.