Parenting time tends to take over most of the hours that would have been work-time, on weekends. At least until your kids are old enough that they don't want anything to do with you anymore (or so I hear).

With kids it's usually possible to do something either productive or fun alongside the whole kid-taking-care-of thing. It's just very hard to do anything you like that is productive or fun. You gotta roll with the punches. Typically things that require few unpredictable interruptions and that can't be done with your kid(s) (which varies greatly with their age) are out of the question unless they're in bed or someone else is watching them. Or you turn on Babysitter Television, of course.

This is very true in my experience. I covet and zealously guard the hours between 8pm and my bedtime and/or ~6am and when the kids wake up. It is very hard to do deep intellectual work when you have kids around, but easy to get more rote tasks completed.

It's a big part of the reason I do a lot of jobs with my kids. I teach them how to cook, we grocery shop and I discuss how adults purchase things, I fold the laundry in front of TV with them, etc. My 4-year-old son has shown a lot of interest in my tools lately and last week he helped me repair a cupboard. My deep intellectual work is after a nights rest when I wake at 4am (I go to bed at same time as my children, ~8pm).