(This post has been a long time coming from me...)
I remember fanatically loving the "Teenage Mutant Ninja Turtles" movies as a child (4+) and would watch all three
at least once a week (sometimes all three daily, for a week), and I would imitate flips, wall-runs, and other stunts in the films. As I got older I became more interested in Jackie Chan and his style/movies and would imitate him (I still do

), until I started to hear about others such as Bruce Lee and Jet Lee, and got more interested in martial arts, which never really panned out for me...
However I believe what made me start doing/wanting to do actual Parkour & Free-running was in late 2003-2004 when I began hearing about David Belle online and then seeing more and more videos of him and others. Until I finally said "Yep, I am going to be like them, and do that."
So far it has been a long journey with ups and downs, fully quitting and then re-starting. But it has been over the past several months (re-re-re...started in August) that I have begun to take it really seriously with proper diet, excercise, stretching, training, martial arts and such.