Crazy Monkey Games brings us Pandemic 2. Choose your disease method, upgrade/evolve it to be more infectious, resilient, or deadly, and unleash it into a random region on Earth. You want to infect everyone before borders and airports are closed, and kill everyone before a vaccine is created and distributed. Most of it is random luck, and if this game teaches you anything, it is that Madagascar is the safest place to be before an outbreak. Play it here.
Previous time wasters:
2. Falling Sand