The Starcraft Command
The Reaver Drop
The Reaver drop at one time was extremely deadly. When 1.04 patch came out it slowed the Reaver Drop down, but it is still a very deadly technique. Here is a build order that will leave you vulnerable to early attack, but if you get the Reavers fast enough you are almost guaranteed a win.
Begin by building 7 probes. With the 7th probe build a pylon. Build 2 more probes and with the 9th probe build a Gateway. Build another probe and with the 10th probe build an assimilator. Build 2 more probes and put both of them on minerals. When you have 200 build a Cybernautics Core. Then when your Assimilator is done take 2 probes off of your minerals and begin to get gas with them. Then build 2 more probes and put them both on gas. Keep building probes for minerals. Build 1 Zealot and begin scouting with it. Build another pylon and then get either 2 or 3 Robotics Facilitys, then a Support bay. Make sure you have enough pylons. If you get 2 Robotics Facilitys build two Reevers then one Shuttle. If you get 3 Robotics Facilites get 2 Reevers and a Shuttle (obviously). In the Support Bay begin upgrading to be able to have 10 Scarabs. As soon as your Reevers come out begin to build Scarabs. When your Shuttle comes out immediately load the Reevers in and then go drop them. If this fails I would suggest getting a total of 5 Robotics Facilities and expanding, if you plan on continuing to go Reevers. Then in 4 of the Facilities build Reevers and in 1 of them build Shuttles.
This is a very deadly attack if you do it fast enough.