When I went to technical college, I started getting interested in my own things more and more. Normally that's probably not a good thing for someone with ADD - but in my case it turns out that I was interested in anything related to programming and Unix. This required extraordinary amounts of reading. Ridiculous amounts of reading of quite technical material meant that I had to develop concentration, and now I ironically don't have a deficit of attention, I have hyper-focus on the task at hand and get irritated if someone tries to distract me.
Funny how life happens sometimes.