I would say:
5v5
-cm mode
Entrance fee I would say about 25/team is good. (No experience in this, so this is negotiable). [MIKENOTE: entrance fee is tbd if we go with this tournament]
I would think refs for the playoff are necessary.
Basic Rules:
2.1 Bug using may result in a Default loss.
2.2 Creep skipping/backdooring is forbidden. This means you are not allowed to attack towers or other buildings without creep support.
2.3 "Creep support" means that the tower is in range of attacking creeps - even if the creeps do not choose to attack the tower or vice versa.
2.4 You are allowed to attack any building in enemy base if there are friendly creeps in the base when you entered. You do not have to leave/stop attacking if all creeps are dead. E.g - creeps enter the top entrance of base and start attacking the tower/barracks. You [color=green]can enter the base by any entrance and attack any building as long as you entered while creeps were in the base. You may stay as long as you want.
2.5 Only two Mekansms per team.
2.6 Only one Necronomicon per team.
2.7 Maximum of two euls/guinsoos per team.
2.8 A team is not allowed to buy items for other players, but sharing healing/clarity potions, tangos, ring of health/regeneration, gem of truesight, wards, voidstone, sobimask, Bottle, Perserverance and a courier is allowed. Be careful during sharing because you can accidently build recipe items.
2.9 You can use other heros to buy your items as long as you use your money and they are not used by this hero.
2.10 Completely closing the entrance to either base using earthshakers fissure is forbidden.
From:
http://www.dota-league.com/?section=rules&page=5