If you are searching for things to do with kids in some of USA country you can use links bellow:
Alabama -- Alaska -- Arizona -- Arkansas -- California -- Colorado -- Connecticut -- Delaware -- Florida -- Georgia
Hawaii -- Idaho -- Illinois -- Indiana -- Kansas -- Kentucky -- Louisiana -- Iowa -- Maine -- Maryland -- Massachusetts

To have fun with kids select some of the pages
Michigan -- Minnesota -- Mississippi -- Missouri -- Montana -- Nebraska -- Nevada -- New Hampshire -- New Jersey
New Mexico -- New York -- North Carolina -- North Dakota -- Ohio -- Oklahoma -- Wisconsin -- Wyoming -- Oregon

For family fun days out navigate to
Pennyslavia -- Rhode Island -- South Carolina -- South Dakota -- Tennessee -- Texas -- Utah -- Vermont -- Virginia
Washington -- West Virginia

On the following link you can find things to do with kids in UK.

As shortcut for things to do and where to go with the kids in the USA cities use following links:
Newark -- Phoenix -- Denver -- Reston -- Stockton -- Boston -- Washington -- Los Angeles -- Irvine
San Francisco -- Miami -- New York -- Chicago -- San Antonio -- San Diego -- San Diego -- Indianapolis
Albuquerque -- Anchorage -- Salt Lake City

As shortcut for family days out and day trips in the UK you can also use following links:
London -- South East - Milton Keynes -- North West - Manchester -- Scotland - Glasgow -- Ireland - Belfast
South West - Plymouth -- South East - Southampton -- Wales - Cardiff -- West Midlands - Birmingham
Scotland - Edinburgh