Right now I'm playing Warcraft III, as well as it's expansions, namely DoTA (Defense of the Ancients)
These two are very different.
In Warcraft III, you start off with a Town Hall (if you picked the human race) and 5 Peasants. These Peasants can build structures for you to "summon" Knights, Riflemen, Footmen, Flying Machines, Siege Engines, Priests, etc. These can be summoned in an infinite amount. Also, they can make a special structure to allow you to summon Heroes, which are more powerful than normal "creatures", also they have spells to utilize in battle. However, they can only be summoned once, although they can be revived again, it costs gold. Speaking of gold, you can order your Peasants to mine Gold, or farm Lumber. These two currencies are vital to your quick base expansion. As you get more gold and lumber, you can upgrade your structures. The goal here is to defend your base as well as to attack the enemy base. Whichever team makes the enemy's "main structure" destroyed, they win.
However, in Defense of the Ancients, the gameplay is different. Instead of acting like the King of your base, you play as a Hero. There are 2 main races, the Sentinel and the Scourge. There are 97 Heroes to choose from (as of v.6.67c) with different skills and roles for the team. One hero can be a "tank", which may also be the "battle initiator", who starts off team battles by "blinking" (short-distance teleport) to the middle of the fight, starting off with an instant-activate stun in a large area, for the 3 other heroes to get in position. The other heroes may be the "babysitter", who takes care of the "carry" (which, in Pokemon talk, is the sweeper) as he "farms" gold from killing the enemy creeps (which are the creatures) as well as killing heroes, if the enemy is stupid enough not to run if he has low HP. The "carry" has a huge late-game potential, it is possible for them to beat 5 heroes if they farmed up their items very well. Usually, carries are of the "Agility" type, heroes that have insane attack speed late game, as well as decent armor. Some carries are of the Intelligence (spellcasters) or Strength (tank, stunners) types as well. The last type of hero is a "nuke" or "spellcasters", who has a spell that deals huge damage early-game. Usually they are of the Intelligence type. These heroes are very powerful early game, though their dominance is replaced by the carries late game. There are also "gankers", who usually aim to stop the enemy carry from farming peacefully early-game.
Items are vital to the hero's success. They give stat bonuses, damage bonuses, evasion, movement speed, attack speed, armor and HP, as well as HP regen/sec and mana regen/sec. Carries usually farm the big items, which give damage bonuses, as well as stat bonuses to their primary attribute (Agility, Strength or Intelligence).
Both of these games last 40 minutes to 1 hour, or more. They both aim to destroy the enemy base in order to win.
Did I say too much? >.>
(If anyone wants to play through Garena [I don't have battle.net], PM me
)