I’m turning on the Towny FLAG war mode. The specifics will be a bit different as I configure this, but for the most part wars will work according to this page:
xshade.ca/projects/towny/tutorial/war/
There is a fee to declare a war on an enemy plot. Wars must be between nations. Both the attacked nation and the specific town being attacked must have a minimum number of online players to declare the attack. Neutral nations do not participate in this at all, but the cost for going neutral is 10,000 Sil, as always.
I do not believe that damage regenerates yet if an attack is repulsed, though that is an option they are supposedly working on. So keep that in mind. PvP Towny attacks are going to be destructive.
As listed on the page, only border plots can be attacked. An attack (placing a flag in a plot) will cost the ‘flagbearer’ 1500 Sil. A successful attack will earn that player 2000 Sil (a net gain of 500), taken from the town. Repulsing an attack will cost the flagbearer 1000 Sil (a total loss of 2500), awarded to the town. Taking a town’s HOME block is worth 5000 Sil (3500 gain).
When blocks are taken, they are claimed by the town launching the attack. You very much want to defend your town.
I’m actually not sure what happens when a home block is taken. One way or another, I would be incredibly protective of your home block. I’m looking at all those towns that have their home blocks located at the edges of the town. Keep in mind, if a nation/town is flagged as an Enemy, they are prohibited from using your town spawn.
To attack an area, the flag-bearer (who must have at least 2500 Sil to declare an attack, due to loss costs) places a fence post. This immediately spawns a glowstone ‘beacon’ above the flag and begins the countdown. A wool block and torch will appear on top of the flag post. The flag wool block will turn from green to red. When it is red, the attack is successful. The town’s defenders have 10 minutes to destroy the flag. Yes, that is a lot of time.
Due to being a ‘defend the flag’ style event, blocks in a contested area are largely unalterable (for the time being). However, TNT can be used to kill other players. Only if an attack is successful will the plot be destroyable by the attackers (since they will then own it).
So, A couple questions…
Is this on right now and What did you set the “war.enemy.min_players_online_in_nation” and “war.enemy.min_players_online_in_town” to?
Oh… And 1:40 am? 
Yes, it is on. The defaults are 3 in nation, 2 in town.
Okay, Just checking. I don’t want people to randomly start attacking Alienopolis just because I’m online.