Something which was absolutely fascinating to me - I went to a conference a couple of years ago about how to support kids with LDs. There was a talk about Neurofeedback (which ended up being a sales pitch, but anyway) and I had a go on their Neurofeedback machine thingy where you have to try and relax and when you make the right kind of brain waves which show you are relaxing, a little monk would start levitating and hovering high in the air.
I didn't say that I had ADHD, but as they were demonstrating it on me I could hear the guy discussing what was coming up on the laptop screen just behind me. He commented that I was showing low levels of Beta brainwaves which is usually associated with attention and learning disorders (but then he quickly added, could also just mean that a person is tired or relaxed!) It was pretty amazing to me that it was the first thing that came up when I hadn't actually mentioned it or said that was my reason for curiosity around it.
I found that when I listened to people's conversations and focused on the room and thought about what was happening around me or on the computer screen and wondered how it worked, the monk would plop decidedly down to the ground. When I let my mind wander the way it generally always does, it would fly right up - other people had a go after me and found it quite tricky to make the monk fly, and asked me how I managed to do it so easily. I chatted with them afterwards and they said that for ADHD they generally do the opposite - use software which encourages/trains the use of more Beta brainwaves, whereas the monk was supposed to help train people who are anxious or type A personalities to relax.
I also did concentration and memory testing as part of my medication trial (I'm in Germany and it's different here) and it was interesting to see how medication had an incredibly clear effect on that.
And the parent quiz in Smart But Scattered where you score your own executive functions (in order to see your strengths and weaknesses), up to a maximum score of 7x3 for each skill. I kept getting 8, 7, 6 with the odd 10 or 4. I thought oh, I haven't done too badly, until I read that most adults get scores of around 13-14 in most areas 
and that a score lower than 13 constituted a weakness. I got one single score of 13, and that's the one area I would say I've heavily worked on coping skills. The rest were lower and most of them were single figures, a couple were even the minimum possible score of 3. To be honest it kind of made me feel better - to see I really do have that severe level of impairment yet here I am living some kind of a life and not completely wallowing in a pit of despair. I have wallowed in a pit of despair at times. But I am doing OK.