I go to a school not quite as cush as SugarLand72, but not nearly as brutal as the other posters. I chose my school, in large part, because of its reputation for being so family friendly. Obviously, each parent's experience will be different, based upon family dynamics, the school's attitude toward children, rotation at the time etc.
The key for me is to have 1) a husband NOT in medical school - he's an architect and thus can afford a funky, flexible schedue - he doesn't go to work until 9:30 am, does all morning duty (and also BITES at ponytails, too, TiredMom!) and is available should our 18 mo old daughter get sick, preschool is closed, etc 2) have really good dependable childcare - we do 1/2 day of preschool, our nanny picks her up after lunch and we pay her to be here until 7, although most days we're home early, there is reassurance that we've got our butt covered in case either of us needs to stay late. All this childcare is expensive - close to $1600/month. Financial aid covers childcare expenses and I decided the 3% interest was worth the peace of mind.
I wake/leave early - before my daughter wakes up and often get to the hospitals or clinic early to study - usually in the conference room. That way I don't have to sacrifice afternoon playtime, dinner time, to study. Also, it's just plain easier getting ready in the morning not having a toddler teething on your pager, coloring in your Maxwells, and smearing YoBaby on your scrubs, IYKWIM!
Like TiredMom says, it's all in the planning, we make lunch at night, lay out clothes the night before - we grill up chicken breast, kabobs, etc on Sunday afternoon in the backyard and eat on those for a good part of the week. Thursday night is leftover night. Every Friday night is Pizza (woot!) night. We sucked up and hired a housekeeper - $70 every other week so that, once again, we don't sacrificed playtime for toilet scrubbing.
All "activities" are on weekends. Period. Swim lessons, zoo trips, playdates with our friends. I usually study both Saturday and Sunday afternoon during her naptime - that, plus about an hour every morning, does the trick for me. If I have to do any extra reading/presentations, I do those at night after she goes to sleep - though getting up as early as I do (4ish) means I'm not far behind her when it comes to night-night.
As far as the day to day mommy things, it's totally rotation dependent. But with every rotation thusfar, I've been able to be home by 7 pm on NONCALL nights. We do have to take overnight call and work several weekend days a month. Again, on weekend days I get in early, get my work done well and fast, and then am usually told to "gettoutofhere - go enjoy your weekend" by housestaff and am home by lunch.
I can't imagine parenting any other way - this just works so well for us, my hubby and daughter are both thriving - I think we'll probably shoot to have #2 next year!
) Getting lunches ready the night before helps alot. Getting the kids on routine helps too, so that dad can get them out the door without near the trouble they were giving me! 
