Leave a compiler lying around. (Score 1)

That's how I got started. My dad left his Borland Delphi III disk lying on his desk with a copy of "Teach yourself Delphi III in 28 days", so I took it and installed it on my computer. Eventually I got bored just drawing pretty windows, so I ask my dad how to "do stuff", and he introduced me to pointers, linked lists, stacks, and all sorts of wonderful data structures. The rest, as they say, is history.