Visualize your processes in colorful blobs in a "lava lamp". This is a great way to appreciate what's happening inside your system in a more concrete way. The blobs use color to relate processes of the same kind, size to indicate memory consumption, and speed to indicate cpu usage.
But in addition to being pretty, lavaps is very handy for children to control their processes. With it, my eight-year-old son is able to easily identify and kill processes that have run out of control (e.g. some errant java app has sent his web browser into a tailspin, which happens from time to time).