Evolution, creationism, and intelligent design are words that many people have extremely strong opinions about. Regardless of how you feel about why the laws of nature are what they are, which have evidently allowed us to exist, the evidence for the validity of the theory of evolution with one major mechanism being natural selection is absolutely overwhelming. That said, this is often very hard to communicate to people, especially those with strong biases against what they perceive as the implications of evolution, how evolution works, and why the case for it is so compelling.
Thankfully, there is a person calling him/herself cdk007 making youtube videos like this one to explain how evolution works, and why arguments against it are invalid, with dauntingly demonstrative examples:
This video is excellent, and there are many others (the Bad Astronomer likes this one); I recommend them to anyone who is looking for simple, compelling examples of how this complicated biological process works. In fact, the only explanations that I’ve ever found easier to understand were watching Episode II of Carl Sagan’s Cosmos series and watching the off-Broadway play Trumpery, a fascinating play about the scientific and personal struggles of Charles Darwin (and I think Michael Cristofer deserves to be showered with accolades for his performance as Darwin).