It was the PinBall arcade software that got me into it. I am probably younger than most at 25 so never really grew up with PinBall. In fact until recently when I went out LOOKING for pinball machines I had only seen a few in my entire life.
The PinBall arcade opened up a whole new world for me and impressed upon me just how fun PinBall could be. From there it got me out and around my city looking for locations where I could play real pinball machines and I have now bought my first machine and am looking to buy more.
You know its an odd thing. There are obviously not many physical machines out there because the customers are not there to support it but at the same time I cant support the machines if they dont exist. Catch 22 I guess. Had I had the luck of randomly running into a machine before onsite my obsession may have developed earlier than it did.
*edit*
It also helps from a personal collection point of view that I am old enough now that I am at a point in my career where despite the lack of available on location machines I can afford to indulge in my hobby from a collectors point of view. Something even two years ago would not have been possible for me.
After reading the posts above too I must concur. I have been a console/PC gamer since 93 and sitting down with the old Apogee/ID games but the last few years have been slowly losing my urge to sit down and play anything for any length of time. PinBall now seems to have taken its place.