I tried to add to this conversation a few days ago, but touched the wrong thing on my tablet and POOF it was gone! I decided that frustration was something I didn't need any more of, so I went outside to do things on my 'to do' list.
My OT recommended Lumosity to challenge my brain, which I did for a while. I soon figured out that I did better if I actually read the instructions on how to pay the games rather than just diving in and figuring them out gave me much better scores, But I am a guy, and that coupled with the endless emails to buy it, I was driven past my tolerance level. I now do Sudoku and MS Solitaire. They help get my brain in gear before I go out and face the day.
My real challenges are the projects I find myself doing in the yard, garage or house each day. Like finding the rocks that will fit together properly to complete my retaining walls, engineering a system to capture and use rain water for my drip irrigation system in my vegetable garden. These are the things that are real challenges and bring the greatest rewards when you are able to get them to work. When I need to rest from these projects, I come inside, sit in my recliner and start one of the afore mentioned games. After about a half hour, I wake up, finish the game and then go back out to work.