While playing a game, press ~ to display the console, then type "sp_cheats 1" 
to enable cheat mode. Enter one of the following codes to activate the 
corresponding cheat function. However, cheats cannot be enabled in multi-player 
mode.

Result - Cheat Code
Toggle God mode - god 
All weapons - give weapons 
999 health and armor - undying 
No clipping - noclip 
Invisibility - notarget 
Third person view enabled - cg_thirdperson 1 
Third person view disabled - cg_thirdperson 0 
Set third person view range - cg_thirdpersonrange [1-100] 
Obtain indicated item - give [item name] 
Level select - map [level name]