My wife and kids (one almost 3, the other 11 months old) recently returned from an extended Germany vacation, after which I discovered that it is much more exhausting to have children that suffer from jetlag than to suffer from jetlag myself. For the first couple of days, 2 AM to 4 AM suddenly became play time, dinner time, potty time, etc. Not much fun when you need to get up early to go to work. ;)
After about a week, they appear to have finally settled back into their regular schedules. Definitely something to consider if you’re planning a short trip to a place with a significant time difference (Germany / San Francisco is 9 hours), as your kids will likely spend a better part of the trip adjusting to the new schedule (along with all the crankiness that goes along with this), only to have to adjust back to the old schedule after the return. Not that you can do much about it…