Warcraft 2

* Cheat codes:

IT IS A GOOD DAY TO DIE Invincibility
GLITTERING PRIZES 10,000 gold, 5000 lumber and 5000 oil
VALDEZ 5000 oil units
SPYCOB 5000 oil units
HATCHET Get wood in 2 chops
MAKE IT SO Speed up production
TITLE Increases the speed of your units
NOGLUES Disables magical traps
SHOWPATH Displays entire map
ON SCREEN Displays entire map
DECK ME OUT Upgrades all technology
EVERY LITTLE THING SHE DOES All spells (And Paladins Oh Joy!)
UNITE THE CLANS Instant victory
YOU PITIFUL WORM Instant defeat
NEVER A WINNER Remove victory
THERE CAN BE ONLY ONE Ending
TIGERLILY Enable ORCx and HUMANx cheats
HUMANx Warp to Human mission x
ORCx Warp to Orc mission x
FASTDEMO Demo starts earlier
UCLA Shows "Go Bruins!" message
DAY Shows "FIEF" message
NETPROF Laser display
ALLOWSYNC ???
DISCO Changes the music

* Building Transport
Put 6 skeletons on a transport and let them run out of energy there. The next 6 things you build will get cloned on the transport (this includes buildings.)
Then you can disembark them just like you would guys and the buildings will be instantly built.
Note that they may be built on top of each other.

* Exploding Sheep
If you click on a sheep (or other animal) enough times it will explode.
This won't do any damage to your enmies, but it is good for a few laughs. :)

* Construct Buildings Faster
To speed up development without using a cheat code, have some of your peasants repair the building you're constructing.

* Cheat Without Getting Caught
If you want to use codes to beat the game, but don't like to be ranked "cheater", you can get as far ahead in the game as you want using cheats, then save your game.
Quit WarCraft II, then restart it.
Load your game, then save it in another file.
Quit to the menu, load the second game you saved, and finish the level to remove all stigmata.
(Information from Cheat Machine)