heres a ten minute bbc documentary explaining it a bit [ame="http://www.youtube.com/watch?v=qzZDlXji0e0"]YouTube - Quantum Mechanics for Dummies - Electrons Are Weird[/ame] youtube also has a lot of educational lectures on it by standford and MIT if you search for quantum mechanics. In a sentence: Everything that can happen, does.
In laymens terms, it is the study of particles on the smallest possible level. Like watching electrons, and protons and how they react when being observed..