90% of your computer cycles are wasted

I usually work with the task manager open as sort of a habit so I might have a general idea when my computer might start lagging on me, and it does from time to time. But for most of the time, the task manager usually has your CPU idling at about 3~5% of it's max usage for most of the time.

For all the impressive CPU speed we've got with growing clock speed and then now with the growing number of CPU cores, we just aren't using the computer to their maximum potential and it is going to stay that way for years to come-- it's just that most programs are very dependent on human input.

But what if we could reduce the need for a computer to try on human input and perform useful work while we are not around? I believe that there is an immense opportunity for software like these. Seti@home did something like this but it's more for charitable work. What if background processes could be created for a PC to your work while you're not using it?

To me, I think that would be awesome.