Your probably asking yourself, why 5, why not 6, why not 10 or 12. The answer is this: if your opponent immediately goes for lurkers, dark templar, or vulutures w/ spider mines, then he'll have it by the time you have 6 Zs or more. Why not attack with 1 or 2 zealots -- not enough. I find that 5 zealots is the magic number when rushing, especially when your ally joins in with this rush.

Build 8 probes. When the 8th probe is 1/2 way built, warp in a pylon. Build 2 more probes (count is at 10/17). Warp in a Gateway. Build 2 more probes (count is at 12/17). Warp in a 2nd Gateway. Build 1 more probe. (count is at 13/17). Warp in a pylon. Build 1 more probe. (count is at 14/17). Warp in a Zealot and another probe. (count is at 17/17). When pylon warps in, build 2 zealots, one from each Gateway. Build another pylon. Build 2 more zealots. Continue massing probes for collection. Attack the enemy!

The idea of this rush here is to catch the enemy off gaurd, while he is either teching up or wasting his time with a 2nd base or defense. If the enemy has more than a couple towers, like a few, then hold off your attack and attack his ally. The guy with the defensive towers will not be able to participate in helping him out! Hopefully, you and your ally will win. This attack is really great when you also have 1 or 2 allies participating in this attack. Caution: Not recommended against Zergling rusher. And remember, after the rush, get some defense like photon cannons at choke, tech up to dragoons with your cybernetics core, build an asslymator and many more support units. Extra pylons and Gateways wouldnt hurt either.

CreepColony's Opinion: This will probably work against Terran and Zerg, but maybe not against Protoss, since most Protoss players build cannons pretty early in the game, and they are really easy to build.