Annex A fourth multiplayer mode, called "Annex", was made available in the third patch for Gears of War on April 9, 2007. In Annex, teams win by keeping control over key map locations, or objectives, long enough to collect a winning number of points. Every map has two to five identified objectives available for capture, with one objective active at a time. Objectives are based on map weapon-spawn locations and have a potential value of 60 points toward either team’s score. Teams collect those points by maintaining ownership of an objective until all its 60 points have been distributed. Every second that a team controls an objective, the team gets one point. When an objective falls to zero points, the next objective is selected at random.
SOURCE:
http://en.wikipedia.org/wiki/Gears_of_War#Versus_Mode