Here's a (very long) description of these modules:
A Series: The Slavers' Series - The PCs are hired by a group of independent towns on the Wild Coast in the World of Greyhawk Setting. Slavers have been raiding the towns, which have put aside their petty squabbles and hired the mid-level PCs to track down the source of the slavers and destroy them. These were originally early tournament modules and come with 8 pregenerated characters (including a bearded dwarven female!) and (unlike the other modules listed here )a scoring system for running each multi-round module as part of a grand tournament.
A1: Slave Pits of the Undercity
Round One - The party runs a gauntlet through the "back door" of a slave base in a ruined city.
Round Two - They descend into the sewer-dungeons to gather information and disrupt the slaver's operation.
A2: Secret of the Slavers' Stockade -
Round One - The Party stealthily infiltrates a well-guarded fort guarded by humanoids.
Round Two - They explore the dungeons and learn the location of the Slavers' home base.
A3: Assault Upon the Aerie of the Slave Lords -
Round One - The party runs a linear gauntlet through secret tunnels leading the the city of the slavers.
Round Two - The party explores the Slavers' City, contacting spies and discovering clues to entering the slavers' dungeons.
Round Three - The party rages through the slavers' headquarters and face off in a battle royal against 1/2 the chief slave lords (who are all interesting characters). The module does railroad the PCs to force them to be captured.
A4: In the Dungeons of the Slave Lords -
Round One - The party is thrown into the monster infested stygian pits beneath the city wearing only loincloths. They must use the resources in the dungeon to improvise light, weapons and a means of escape.
Round Three - The PCs escape, they fight the last of the slave lords, all during a volcanic eruption that destroys the slavers' city.
The G series - Against the Giants
These are also very old (1976-77) tournament modules that are basically high level hack n' slash without a real scoring system. Giants are raiding the lands of Ratik and Geoff in Greyhawk, and they hire a group of high level PCs (provided) to kill the Giants and discover what force has organized them.
G1 - Steading of the Hill Giant Chief - The PCs attack a wooden stockade where the Chief is holding a summit meeting of Giants. There's a stockade, a dungeon, lots of loot, and tons of combat action. Clever PCs can really get the jump on the bad guys if they plan well. Foolish play results in the whole place being alerted. Clues lead to G2.
G2 - The Glacial Rift of the Frost Giant Jarl - The PCs get telported (or travel overland) to a remote Glacial Rift/caves where the Frost Giant Jarl lives. They assault his frozen home and kill everything. Clues lead to G3.
G3 - The Halls of the Fire Giant King - This dangerous dungeon adventure takes place in the volcanic Hellfurnaces. Again the PCs are teleported. If they alert the Giants, they are in big trouble. If not, they can actually take advantage of some of the Giants' political squabbling and personality quirks to get the jump on them. They encounter the true masterminds behind the Giant raids: Drow Agents. A tunnel leading into the Underdark allows them to take the fight to the Drow homeland and modules D1-D3 plus Q1.
The D Series DROW series/Descent into the Depths series
This is the late 1970s tournament series that originated the D&D "Underdark" setting. The PCs have a poorly marked Drow map showing different kinds of tunnels and strange symbols indicating encounters. The trip through the tunnels is a dungeon adventure on a wilderness map scale. When they run into an encounter (marked or not), the play moves to dungeon crawling scale. Each module has pregenerated characters and features a single large dungeon encounter (plus a few smaller preliminaries).
D1: Descent Into the Depths of the Earth - The party becomes acclimated to the Underdark setting. They encounter a major obstacle -- a huge cavern populated by communities of dangerous creepy-crawlies. The PCs have to make it through this cavern to continue their mission to the Drow homeland.
D2: Shrine of the Kuo Toa - The party encounters more wierd and deadly small caverns, culminating in a vast temple complex of the degenerate Kuo Toan fish men, devoted to their mutant lobster god. The Kuo Toa are vicious and inbred, but are also apathetic. Smart parties can forgo exploring the complex and bluff their way through the checkpoints to continue their journey. Hack n' slashers who frontally assault will alert the complex to their presence and have a *tough* time.
D3: Vault of the Drow - The party uses all their wits to survive this dungeon+wilderness+urban adventure. They enter the vast cavern where the drow live and track down the people in charge of the campaign against the surface world. This leads them to the demon queen Lolth. This adventure is so large in scope, none of it's elements are fully fleshed out (you could fill a hardback book just detailing the Vault). The PCs end up pursuing Lolth through a gateway into her home plane on the Abyss itself.
Q1: Queen of the Demonweb pits - the finale of the series is by artist Dave Sutherland III, not Gary Gygax (who did the G and D series -- he was working on the T series at the time). This multiplanar exploration module bends all the rules of the game, as spells and magical effects function differently on Lolth's home plane. The Demonweb is a wierd series of moebius strips that the players traverse. A series of doorways lets players encounter lolth's minions and gates into other worlds where Lolth is trying to infiltrate and take over. These worlds are also not fleshed out (the scope of the module is huge -- you could run a multiplanar campaign with just Q1 as the basis). The battle culminates in the PCs entering Lolth's "Spider-Walker-Warmachine", killing off the crew and beasties, and tracking the queen to her private lair for the final battle. It's very hard to beat her (she keeps regenerating her HP each time until the final battle)...
S Series - "Special Series" of tournament modules featuring high level play in unusual settings.
S1: The Tomb of Horrors - One of the first tournament modules produced. Classic killer dungeon with pregenerated PCs (so the players won't be too hurt when they get burned/sliced/gender-switched/turned to a pile of goo). PCs find a forbidding tomb of the legendary demi-lich Acererak. It's really dangerous, evil and scary. Full of devious tricks and traps, and common sense tests: you fail to show common sense, and you die instantly, no saving throw!
S2: White Plume Mountain - another favorite dungeon crawl. The PCs are hired by wealthy collectors when their ultra-powerful magic weapons are stolen by the ancient wizard Keraptis. He's challenged them to enter his mountain dungeon and take the weapons back. There's a poem full of riddles, all sorts of bizarre tricks and traps, and some truly memorable battles. The weapons are too powerful, and will unbalance a campaign though (one is a knockoff of Stormbringer).
S3: Expedition to the Barrier Peaks - A science fantasy adventure that takes elements from an OOP TSR RPG called Metamorphosis Alpha (the ancestor of Gamma World) and plops them into a D&D game. The PCs investigate a meteorite that turns out to be a jettisoned section of the gigantic space ship. They explore the "dungeon" and try to figure out how the run-down tech operates before being killed by mutants/monsters/robots and the malfunctioning food replicators.
S4: Lost Caverns of Tsojcanth - Massive wilderness & dungeon adventure that included a supplement book with tons of new monsters, spells and artifacts. The PCs a remote mountain range in search of the dungeon HQ of Iggwilv the evil mage queen. The mountains are deadly, the caverns are huge (and deadly), and if the PCs are clever they can figure out how to open the doors to Iggwilv's treasure hoard and the final guardian (and a fantastic final battle). This module also has links to T1-4 and a rare module WG4: The forgotten temple of Tharizdun, which is optionally located in in the mountain range. Trivia note: S4 was based on a very early tournament adventure (Lost Caverns of Tsojconth) that was the second module ever written for D&D, sold at Wintercon V in 1976.
The "T" Series - Gary Gygax's famous dungeon crawl against a ruined temple that houses an ancient evil. Monte Cook made a d20 sequel for WOTC. Troika Games (designers of the Fallout and Arcanum CRPGs) are making a computer version of the Temple due out next year.
T1: Village of Hommlet - Thoroughly details a medieval village, it's history and NPCs as a home base for a starting campaign. The default setting is the Viscounty of Veluna (a fief of Furyondy) in Greyhawk. There is a ruined moathouse to explore (an destroyed outpost left over from the war against the Temple of Elemental Evil) and a link to further adventures in the Temple. This adventure has some tough encounters, and was designed with a 1st Edition party of 8 characters in mind.
T1-4: The Temple of Elemental Evil - Includes the original T1 in a mega campaign book. Details the town of Nulb, the ruined Temple, and the many dungeon levels beneath it which are harboring a terrible secret. You could run an entire (short) dungeon crawling campaign just using this book.
here's a good website for finding info about early modules:
The Acaeum