Temple of Elemental Evil, The-GOG

Thus begins your adventure within the Realm of Greyhawk. It is an adventure that will lead to the source of a deep and abiding mystery, to the very core of evil itself.
An evil demoness founded a cult dedicated to exploring evil in its most elemental forms. This cult was based in a temple just outside the village of Hommlet in a vile shire known as Nulb. Soon, this cult rose to rule the region with tyranny and grim times of chaos and violence ensued. Hard-fought battles were waged and the war was eventually won by the good armies of nearby lands. The temple was razed, the villains were imprisoned, and order was restored. The temple itself faded into distant memory. Until now...

A classic RPG based upon the famous Greyhawk adventure and using the D&D 3.5 ruleset
Parties of up to 5 adventurers and up to three NPCs with 9 starting points, depending on your alignment
Tons of different monsters, feats, spells and magical items