File Extensions Game

[Honno]

.blb (blockland brick file)
.ter (torque terrain file)
.sys (kernel mode driver [ring0])

[Ad Bot]

[Hansome duded]

.txt (text file)

I think this has been done already.

[Ipquarx]

.opus (Opus music file)
.flac (Free Lossless Audio Codec music file)

[mp7964]

.brown town - an xml-based format i use to store savedata for a platformer i'm not working on

[Honno]

.bob (loving lego island 2 archive)
.bod (loving lego island 2 archive)

[Hansome duded]

.brown town - an xml-based format i use to store savedata for a platformer i'm not working on

I'm cracking up.

[eboyblue10]

.psd (photoshop document)
.indd (indesign document)

[mp7964]

I'm cracking up.

i also use .cunt for a batch-like scripting language that binds C# Actions to a keyword that can be called from the console or a .cunt file.

[BluetoothBoy]

.tiff - Image file
.raw - Raw image file from camera
.prj - Nanostudio project folder/file
.nsp - Compressed Nanostudio project file
.mtl - .obj material data
.skp - Google SketchUp file
.rtf - Rich Text Format
.reapeaks - REAPER waveform data
.vst - DAW plugin
.au - Audio Unit DAW plugin (Mac only)
.aep - After Effects project file
.glsheet - Google Docs spreadsheet
.ai - Adobe Illustrator file
.vob - Obscure video format
.dmg - OS X disk image
.prefab - Unity 3D prefab file
.asset Unity 3D asset file
.sunvox - Sunvox tracker project file
.dae - Digital Asset Exchange file
.log - Log file, go figure
.mid - MIDI file
.qtz - Apple Quartz Composer file
.docx - Microsoft Word document
.ogg - Underrated audio format
.m4v - Video format
.m4a - Video format
.ny - Audacity plugin

[takato14]

.MLVL (Metroid Prime's map format)
.ECM (Compressed PSX disc image)

[Honno]

Lets take it up a notch and post the header information

[Wiiplay123]

.vmap (Source Engine 2.0 map file)
.roobicks (My personal file format for making maps for a game I stopped working on called Roobicks, which is a lot like pgm, ppm, and pbm.)

[foulprairiedog]

.wtf (it's a secret to everybody)
.sai (paint tool sai)

[ZombieDude]

.dae - collada DAE model
.obj - wavefront object
.tga - TARGA raster graphics

[Daswiruch]

.db_ - CAD File