Push and pull, back and forth, attack and flee. Dota 2 is an epic tug-of-war that requires sharp skills, good timing, strong teamwork, and a whole bunch of flashy magic spells.
The goal is simple: Command a hero bristling with magical abilities to attack the enemy's heroes and structures, until their base is destroyed. Of course, the opposing five-person team will be doing the same. Knowing when to defend and when to attack is key.
Use the gold you accrue by killing anything to buy items that upgrade your attributes and abilities.
If you've mastered the 102 heroes, check out League of Legends, which plays slightly differently but is just as fun (and free).