On my iMac I have a program called "Memory Clean."  It's a cool, little third party application that lets me know on my dock how much memory is being used at any given time, which applications are using significantly high amounts of it and has a quick function that "cleans" out the used but unnecessarily overloaded memory so the damn machines can move more quickly, more smoothly, and more efficiently.  I like it because A) it works the way it's supposed to and B) it gives me a sense of control I otherwise wouldn't have.

As tired as the "Computer Brain = Human Brain" metaphors are, this is one more of that stripe.