Military simulator Arma 3 begins beta operations near the end of this month, June 25th. New vehicles, weapons, as well as co-op, multi-team and defence scenarios are included in the test for beta recruits.
Bohemia also integrates Steam Workshop directly into the Arma 3 mission editor, although this might be absent the beta. Currently Arma 3 is being put through its alpha paces.
A new natively armed faction is being introduced also for Altis and Stratis. Of course if you're too impatient you could always signup for the alpha build.