Editing Textures and Sound while Ingame Source

METHOD
Ingame in most Source engine games, features exist to refresh the game sounds and textures without reloading a level, When replacing sounds and textures using a combination of software including the most accesible GCFscape, VTFedit, Audacity and Wavosaur, modifications can be viewed immediately using the console commands snd_restart and mat_reloadallmaterials. Features for refreshing other content such as Models and Programming are perhaps covered by the commands flush and flush_unlocked (correct me here if I'm wrong). Using these things alongside the console commands soundlist to get a list of cached sounds and most useful surfaceprop to get the material and model files under the crosshair, (properties of surface and entity you are looking at) worlds and sound schemes can be dynamically re-built and re-painted.
EXAMPLE

Original Sign as seen in Half-Life: Source,

console command entered while looking at the sign:
surfaceprop

Console came back with:
Hit surface "metal" (entity worldspawn, model "maps/c1a1.bsp" Opaque. ), texture "HALFLIFE/SIGN9"

Proceeded to change the material in the directory Materials/HALFLIFE/SIGN9

and then used command:

mat_reloadallmaterials

Final product with material made of first paragraph of this post:

The same process is done with sounds using the snd_restart and soundlist commands or SourceSDK or browsing GCFscape for sounds (and/or materials). Have fun with this, here's the product of some time I spend in Half-Life: Source with this feature: