I just finished playing this game for several hours, it's awesome. It's like minecraft but with WW1 weapons and Vietnam settings, the blues generally tend to be the 'tunnel-rats' (or Viet-KONG as I call them).
It's just come out in beta and is pretty basic, I spent half of my games making tunnels and rallying blues for an all-out rush on the greens (three times, hey, that's what happened in Gallipoli, and we got cut down, like the ANZACS. Well my school did have it's ANZAC ceremony today).
Also, there tends to be a lot of insults traded between teams based on their colours.
Download at ace-spades.com