New grads/young professionals track me down regularly asking for "career advice" (a job). People my age/older email me about potential job opportunities. Coffee with either of them is pretty effortless given that both of them will typically come to you. Meetups[0] after work usually start at 7. I probably get to about 3 or 4 a month which is plenty to build a superficial network outside of my immediate friends and family. I don't have children. Even if I did though, trading 2 nights a month my significant other for personal/career networking isn't all that unreasonable. A friend of mine runs a meetup and he has 3 kids.

I sleep 7 hours, I'm at work/commuting 11 hours. That leaves me with 30 hours on weekdays to divide however I please (obviously there are other basic sunk costs like basic hygiene and eating). I've found that once I quantify the time I have in life, it's a lot easier to notice when it's available and be productive with it. I'm really not even one of those super motivated people. I just like to be conscientious of my free time.

[0] http://www.meetup.com/