Game: World of Tanks

If you happen to be male and aren't a pacifist, I don't need to explain the allure of driving a tank to you. For everyone else, let's just say that especially when it's not in the real world, there's just something cool about commanding several tons of metal, crushing things beneath your treads and blowing stuff up. World of Tanks lets you do all of that in 30-player tank battles on your PC - and it's free.