Battlegrounds:
These are very competitive battles, they take place in special closed lobby maps with 2 teams. One of the teams is ONLY Alliance (10), and the other team is ONLY the Horde (10). They both try and capture the other teams flag and kill the enemy team players in the process. If you kill an enemy team player you wil get Honor Points that can be saved up and eventually spent on Items at a Honor Points vendor. Now if you win you will get some extra points.