Press the tilde button and enter any of the codes and press enter: 
Effect - Code 

Third person view - behindview <0 or 1> (0 means off 1 means on)
Flight mode - ghost 
Disable flight ? walk 
Full ammunition - fullammo
Record demo ? demorec 
Stop recording - stopdemo 
Play demo ? demoplay 
God mode for player - god
God mode for team - godteam 
God mode for terrorists - godterro 
God mode for hostages - godhostage 1 
Disable god mode (hostages) - godhostage 2 
All the god modes ? godall 
Game never ends - toggleunlimitedpractice 
Walk through entities ? togglecollision 
View threat information ? togglethreatinfo 
Kill all terrorists - neutralizeterro 
Disarm all bombs - disarmbombs 
Deactivate IO devices - deactivateiodevice 
Rescue all hostages - rescutehostage 
Disable morality - disablemorality 
Summon all terrorists - callterro 
Invisible to terrorists ? playerinvisible 
Terrorists surrender on sight - tsurrender 
Terrorists shoot wildly - tsprayfire 
Terrorists only fire at you - taimedfire 
Terrorists all run away - trunaway 
Terrorists go back to normal ? tnothreat 
See all terrorists on map - rendspot 
Hostage threat information - togglehostagethreat 
Set hostage position - sethpos <0-5> (0 standing, 1 kneeling, 2 prone, 3 fetal, 4 crouched, 5 random) 
Reset hostage threat - resetthreat 
Next hostage animation - hna 
Previous hostage animation - hpa 
Animate hostage - hp <0 or 1> (0 for no loop, 1 for looping) 
Show field of vision - showfov 
Show weapon direction ? gundirection 
Show terrorist/hostage routes - route 
Show all map routes - routeall 
Remove all NPCs - killthemall 
Remove all terrorists - killterro 
Remove all hostages - killhostage 
Kill all Rainbow operatives ? killrainbow 
Remove opponents - killpawns 
Game modes - sgi 
Resets all cheats ? resetmeall 
Quit game ? quit