How to start WWIII in no more than 200 days:
Take SimCity and AIM.
Since the sizes of the tiles in SimCity are known to be 16 meters on a side, and "road" tiles take up the full width of a tile, practically speaking it means that you can generate 2 miles by about 52 feet of pavement per week. Once you save up for 100 days, you can make a rectangle of pavement that is 2 miles long and nearly 750 feet wide.
So, you use AIM to link up with Kim Jong-il, the Supreme Leader of North Korea. By 50 days, your connection will be strong enough for him to take your advice that he should begin bringing serious amounts of military paraphernalia to a predetermined city alongside the border with South Korea, over the next 50 days. When you hit the 100-day mark, instantly pave over a 750-foot width of the DMZ near the city. All the walls, mines, fences, guard towers: all flattened and conveniently drive-able on. Since you've reached this magic number of 100 days, if you now tell Kim Jong-il to invade South Korea with all the the military power he's amassed, he will do so.
The second Korean War will begin, the USA will get involved, and then China and Russia get involved, and then the nukes start flying. If by some reason this doesn't happen naturally, use AIM to link up to President Clinton, wait another 100 days, and then convince him to start launching 'em.
Sit back and watch the fireworks.