Press the tidle(~) to bring up the console and enter any of the 
following "Codes": 

Code        Result
------------------ 
WEAPON    - All Weapons 
RESTORE   - Full Weapons and Energy 
CLIP      - No Clipping 
GOD       - God Mode 
KILL      - Kill All Monsters 
SCAN      - Motion Scanner 
RESTORE   - Full Weapons and Energy