One thing you left out is which airport you are flying into. That would help others give you a little more detailed info.
We're flying into JFK!!
What time of the day is that 11 hours . 8am - 7pm? 4 pm - 3am? is it 11 hours between flights, or 11 "free" hours taking into account landing and disembarking, and then check-in and security for your overseas flight, You need to be at the airport at least 2 hours before an international flight, maybe more.
What day of the week ? Traffic differs so that could make a big difference in your plans.
And how old are the kids and what are their interests?
Keep in mind you may not have 11 hours. For instance, if your flight from Orlando is scheduled to arrive at 12pm and your onward flight to the UK is due to leave at 11pm - you need to be back at the airport by 9pm, and it's probably going to be about 1pm by the time you're ready to leave the airport.
That said, 8 hours is still plenty of time to get into Manhattan. You could do a layover tour with a company like
They will help you with transport, organize a custom itinerary and get you back to the airport on time.