Pirates, Vikings and Knights 2
Is a free HL2 Mod, if you have any Halflife2 platform game,
inc cs:s and sometimes i'm on dod:s...
But yes, source games = you can use this Mod and it is Free,
lots of good times and novelties.
Aus community is poor, so usually play in U.S.
but I tried to get a community going for a bit.
PVK2
It isn't much like Age of Chivalry but that is free mod too.
for those who don't know, counter strike was a mod of day of defeat,
so mod doesn't mean it lacks anything..
PVK2 has dragon maps where you can fly dragons around and stuff,
but it is a lil awkward at the moment while it is being developed...
I love how it is always changing and so incomplete,
makes for crazy fun... like randomly launching off ladders,
50ft into the air over the ship you were trying to climb on and unload your booty.
You can fire cannons and fight on ships caught over a whirlpool,
or actually the variety of maps is huge.
http://steamcommunity.com/id/anemonebulae 
