GTA: SAN ANDREAS (PC)
Type these during gameplay - there is no console, you just type.

HEALTH / ARMOUR / WANTED
  HESOYAM          Health, armour, +$250,000  (the famous one)
  BAGUVIX          Infinite health (not immune to drowning/explosions)
  ASNAEB           Clear wanted level
  TURNDOWNTHEHEAT  Never wanted
  BRINGITON        Six-star wanted level

WEAPONS
  LXGIWYL          Weapon set 1 (basic)
  PROFESSIONALSKIT Weapon set 2
  UZUMYMW          Weapon set 3 (heavy)
  FULLCLIP         Infinite ammo, no reloading

VEHICLES
  AIWPRTON         Spawn a Rhino (tank)
  OLDSPEEDDEMON    Spawn a Bloodring Banger
  AMOMHRER         All traffic becomes black
  CPKTNWT          Blow up all nearby cars
  BSXSGGC          Cars float away when hit
  ROCKETMAN        Jetpack

WORLD
  PLEASANTLYWARMING  Sunny weather
  CFVFGMJ            Foggy weather
  YSOHNUL            Speed up time
  ALNSFMZO           Slow down gameplay

WARNING: saving after using cheats can permanently flag the save file, and some
cheats (notably the weather and pedestrian ones) cannot be turned off without
reloading. Save first.