Unless ODST drastically changed the 4v4 gameplay, the only game on that list without well-established and dominant teams would be Left 4 Dead, yet you'd still get destroyed if you were a new team since it's been going on for awhile.
Halo should have a top Halo 3 team show up.
Gears of War 2 will have a top Gears 2 team show up.
Street Fighter 4 will get an active LAN-er to show up.
CS 1.6 and CSS will get top regular season CEVO teams to show up.
So your hope would be to either have an established team for L4D that will practice a lot in order to place top 3 or you'll get lucky and not many good teams will register and they'll face each other, leaving you with second or third in the other games.
Don't enter these to win, enter them to have fun. Unless there's some hidden member of the forums who is high-up in CEVO on a CS team, chances are you won't stand a chance. But, competition is fun anyways.