The YSP at West Bretton near Wakefield is a superb place to visit for all age groups.
It has indoor galleries , shops, cafes, and a restaurant, plus superb views and walking in acres of grounds. Sculptures are positioned in the grounds, there is a camellia house, a church used for installations or videos, and a walk or free bus takes visitors up to the far gallery and back.
The park itself is free. There is a charge if you wish to drive to the YSP, but it is possible to park free in West Bretton village and walk down to the park past the cricket ground. An exhibition of Jaume Plensa light sculptures, etc, is on till January 22nd 2012, and attracts large numbers.