Most of the time Harvest App does a perfect job. It is a regular timer app but it is quite good at Symantec when you are not working. If sometimes I'm in doubt about what I spent my time one or if I know that I worked on something else that I was timing, I'll look it up in WakaTime. The combination of the too has been the most useful tool for me.
I thought it would be a memory game like Simon [1] where the game prints one line and then your repeat it. If you are correct it starts from the first line but adds another line for you to remember.
I could see the fun in that. Also you wouldn't have the issue of people complaining about right and wrong answers because you would have to write just as it was printed.