Just a theory
Consider this a private mental note to the idiot I talked to a couple days ago who argued that "Evolution is just a theory": Evolution as a process that occurs in nature is a fact. More than that, it is an historical reality, much as the knowledge that the earth revolves around the Sun is now considered more than "just a theory". The idea that humans evolved from less complex forms is a Scientific Theory, which is different from a "theory" as used in the vernacular (in common speech). A Scientific Theory (capitalization is mine) is the highest level of scientific proof available which takes into account all the observable physical evidence and explains every tiny bit of it. While it is possible to disprove (or falsify) a Scientific Theory if evidence is found to contradict it, generally the scientific community is reluctant to raise any possible explanation to the level of a Theory unless there is a huge body of incontrovertible evidence available and the vast majority of scientists the world over agree with it. Even if some evidence arises to disprove the current Theory of human evolution, it will not remove the facts that have been uncovered in support of it, so another Theory would need to explain all of those finds scientifically (and without just appealing to the caprices of nature or the will of nature's God).
There are several other Theories that you might wish to expend your energy disproving if you think you're up to the task of battling wits with some of the smartest people in the world: the Theory of Gravity, the Atomic Theory of chemistry, the Newtonian Theory of mechanics, or my favorite mysterious theory: Quantum Theory.