I thought Strip Display management as it was then was quite fun at the time. Not sure what I'd think now though.
I used lumosity, it was quite good to pass the time but probably did little to improve or change my scores to the nats tests.
I also played a lot of tetris (
Free Tetris | Tetris Friends Online Games I think I used) which was a similar thing, a good way to pass the time but probably did nothing to imrpove my scores.