@androidi: This reminds me of a game we used to play in high school instead of counting rhymes (hey, we were grown ups, right?): we took a chronograph and tried to stop it as close as possible to some predetermined time, usually 10 seconds.
That's a highly predictable event, so there's no reaction timing involved, and yet it's quite hard to nail the time exactly (that would have been an error of -5..+5 ms as the cheap digital watches we used only had two decimal digits) and nearly impossible to do that consistently. I would be surprised if anybody could get an average significantly better than the (roughly) 17ms of a 60fps game loop.
If you have a chronograph lying around, you may want to try that.