Not sure if any one of you already played these games, but I'll explain anyway (all three are Real-Time Strategy games);
Age of Empires I - A really cool game (already old, though) even if the graphics aren't that nice and isn't so historically accurate. It's simple to play; just choose a civilization (such as Greek, Babylonian, Egyptian, Yamato, Choson, etc.) then choose a map. Choose a victory condition; Conquest means to destroy your enemy completely; Standard means capture an artifact or a ruins, or build a Wonder (a massive, expensive building) to start a countdown to victory.
What's funny about this game is that ALL civilizations have the same language (when you click on their units), and it sounds kinda weird. I even made jokes about it when I was a child.
Age of Empires II - Similar to AOE I, but takes place in the Middle Ages. Now more historically accurate - the civilizations FINALLY have different languages. My favorite civs are the Byzantines and the British (Elite Longbowmen pwn). I'm not really fond of sea battles cause the enemy usually spams A LOT.
Age of Empires III - Based on a time from the renessaince to the Industrial Age. This game is far more advanced than the two, and features 3D graphics; cinematics are actually in-game, with the camera zoomed to make it RPG-like. These are the civs; the French, British, German, Dutch, Ottoman, Spanish, Portugese, and Russian. The Iroquois, Aztecs, and Sioux were added in the "War Chiefs" expansion pack; and the Chinese, Indian, and Japanese were added in the "Asian Dynasties" expansion pack.
My favorite of the civs is German...their Doppelsoldners and War Wagons are simply hard as steel. The're just very good units!