Box Forts

A Box Fort, as the name implies, is using crates, and loose objects found in many Halo 2 multiplayer maps and placing them strategically so that you may have the advantage over your enemies. It is best used on the map Foundation on the game types Zombie and CTF. The two positions are hanger number two, and number four; number two being better because it is harder for the zombies to move the metal legs. The other examples of box forts would be blocking the two front doors on Zanzibar in CTF or using the large boxes on Waterworks to block the ramps at the bases

Halo 3
In Halo 3 using Forge mode, it is possible and achievable to make even more elaborate Box Forts and bases. An example would be using crates on High Ground to completely block off the base to the outside environment. The new Forge method that was added in Halo 3 also makes box forts easier, as you practically have an endless supply of them in your inventory. You can also make a sniper tower out of it by stacking them up and put a grav-lift on the back of one.

Heroic Map Pack
In the Heroic Map Pack, especially on the map Standoff it is possible to construct very elaborate forts, even bases large and elaborate enough to fit a Wraith inside.