The map created by Rixiot is based on the principle of Defense Map. Indeed, 2v2 to 8v8 playable (4v4)
An attempt at bringing the competitive edge to the defense genre. Modeled after the 4 man team structure set by the RMCT tournament series. Both teams start from the same gate, but the Defending team has roughly a one minute headstart over the Invading team, with this time the Defenders can set traps, destroy structures, raid supply chests, bolster defenses, etc. The Defending team makes their way to their castle and protects 2 sponge blocks in their keep. The Invaders have 20 minutes to destroy the blocks before the game ends. There are several integrated mechanisms and the map can easily be played in vanilla minecraft.
Download: Nail Map for Minecraft 1.4.7
You can also see all awesome Minecraft Maps here: Minecraft Maps