I just got invited to a group on face book called Halo Wars: Build your own army.

Basically you join the group, then make your own Halo army by creating a group named Halo Wars: Your army name and then you get points for answering questions.

You get to win 5 copies of halo wars for you and 4 mates!

here's the original group for more details

and here's my army if you just want to join

We're called "The Legion Of Brutes"