Facebook games (Zynga) have become very demanding during the last year. While their graphics seem simple and IMHO should not require vast amounts of processing power, I've observed that the opposite is quite true. I often see CPUs on fairly new computers running at over 90% because of one single web page open with a Facebook game running on it.
Power usage on a modern computer is relative to the load on the CPU. Therefore, a computer left on with a Facebook game running while use more energy than a computer left on at idle. I theorize I could measure the difference by taking note of the wattage usage displayed on the power supply. From that I could estimate the kilowatts per hour. Then using the kWh rate on my energy bill, I guess I could estimate the cost of leaving a Facebook Game opened.
I haven't make such measurements yet (I don't play Facebook games). But I will. In the meantime, I'm gonna throw a ballpark figure out there... lets say the power usage jumps 350 watts. That would be 0.35 kWh. Assuming (another ballpark figure here) a kWh rate of $10 bucks, running the game should cost about $3.50 per hour. Leaving the game opened for a whole month would be about $2,500 dollars a month?
Obviously my math went wrong somewhere. Any takers?