Game Design

General

Gamasutra

Gamasutra has some pretty incredible articles covering everything from the state of the game industry to specifics such as texture compression techniques and procedurally generating content.

iDevGames

A Mac Game Developer Community. Yes, such an elusory community exists. iDevGames is a cool resource even for those not creating games for OS X.

Documents

Escapist Magazine

Inform Designer's Manual

The Inform Designer's Manual, the most comprehensive guide to the Inform programming language, includes a wealth of general information on the theory of game design - how to create effective puzzles puzzles, how to guide the player, and so on. Most of this is contained in Chapter 8, The Craft of Adventure.

Software

Wings

My polygon modeling experience is relegated almost entirely to Wings, but I can't imagine any other software package doing so much with so simple an interface. It's free, by the way. My college student budget thanks them.

Engines

Aleph One

Marathon, one of Bungie Studio's very first games, defined the modern first person shooter. Immediately before Bungie's acquisition by Microsoft they released the source to the Marathon Infinity engine. The current incarnation of this engine is named Aleph One.

Marathon Trilogy

Halo was originally rumored to be Marathon IV. Though officially an independent game, the universe of Halo is strikingly similar to that of Marathon, even going so far as to include much of the same armor, powerups, and weapons. The content of Marathon is not open source but is made available for free.

Project Magma

Myth II, another classic Bungie game, was semi-open-sourced, allowing development of the game's engine to continue in the hands of a select set of developers. The Myth II engine is constantly being improved and added to, primarily catering to its huge modding community. It is fairly easy to create a brand new game with the provided tools.

Interactive Fiction

Brass Lantern

Witness lamentations over the commercial death of the genre, learn about IF design and programming, and come to grips with the fact that The Player Will Get It Wrong.

IF Comp

A yearly competition between writers of Interactive Fiction.

Spring Thing

Another competition, this time for much longer works of IF.

Interactive Fiction Archive

The IF Archive contains nearly every item having to do with Interactive Fiction, from compilers to IF-related magazines.