Chaos theory is fairly broad, abstract topic. I'm not expert on it, but we did (attempt to) learn a bit about it in
math class.
What I basically got out of it, is that chaos theory deals with systems so complex, involving so many variables and interactions between them, that they literally appear to any human observer to have entirely random final outcomes. It also deals with simple systems that invariably end up complexifying themselves, as varibles introduce other variables (note the butterfly example above). Chaos theory is often illustrated with fractals, geometric constructions that begin as simple elements, but wind up having so many variables that each individual progression seems to be random, yet in the end they do form a clear, repeating pattern. You could apply chaos theory to many real world concepts, including weather patterns, astronomical phenomena, the human body, random number generators, and so on.
As for Jurassic Park, Ian Malcolm supposedly was into chaos theory (at least in the book, he was). Michael Critchon likened the events on the island to a chaotic system, having so many variables, yet a clear formula for success or failure. As you can probably see, this has fairly wide-ranging implications, as we deal with chaotic systems daily. In fact, you could say that our entire lives are really insanely complex chaotic systems. Our lives start out simple, and spontaneously complexify. One variable introduces another, which introduces two more, and so on.
You could even say the same about the universe itself.