C-7 I always wondered: since you have kids and it seems you work from home, do you have a separate room for work, work in the same room with kids, have your earphones on, work only when they are not home? Or you are a zen master that don't care about noise?
It's a careful balancing act of all of those. I do have an office (I teach trumpet lessons out of it as well), but there's still stuff in here the kids can play with. I also have a TV with my old N64 hooked up to it, so my four-year old loves playing that stuff when I let him. I generally don't work when the kids are both up and active--I either do housework or stuff with them. If the younger one takes a nap, the older one can play in the back yard (I leave window open to watch him) or, if he's been good and has done enough other stuff, he can play games for a while. He beat Ocarina on 3DS, so he's enthralled playing it on N64 and pointing out everything he finds different. I can usually get in about two or three hours throughout the main part of the day, though obviously not straight-through nearly ever. I stay up after everybody about 3-5 nights a week to work for another two or three hours. I'm pretty immune from noise unless I'm working on music (which I do with headphones typically anyways).
So the kids do have a play room (I built them a slide in there too!) as well as their shared bedroom or living room to play in, or they'll bring stuff to the office and play with it. They're perfectly allowed so long as all that stuff doesn't stay in there (it's big, it's supposed to be a second living room for the house). But I can't really get burnt out during the day at least because I'm often doing stuff with them or taking them out for various things or just pushing them on the swings out back for a while. They like watching me do woodworking in my workshop as well.
So I find as much time as I can between making sure I spend quality time with them and teach them things first. I just also believe it's important for them to have alone playtime every day too so they don't become over-reliant on daddy. I also sleep less than I should, but more than I used to! For reference, they're 4 and 2 years old.