MUMBAI, March 11 -- The most common belief is that playing video games is nothing more than just a waste of time. And it may be true if all you do is spend time tapping away like the Fruit Ninja you are or landing a clean headshot in Call of Duty. But there are serious games out there as well. Games that call on players to battle climate change, help them understand how pathogens spread and find cures for viruses, and even educate them about mental illness. Here are some of them....