For those of that struggle with generating entertaining ideas for days out why not visit one of the many castles Britain has to offer, many of which are Castle World Heritage Sites. Here is a list of the castle you must visit.
Wales
Beaumaris Castle Beaumaris, Anglesey, Wales 5 miles NE of Menai Bridge (A5) by A545. 7 miles from Bangor.
Caernarfon Castle Castle Ditch, Gwynedd, Wales In Caernarfon, just west of town center.
Conwy Castle Conwy, Conwy, Wales In Conwy by the A55 or B5106.
Harlech Castle Harlech, Gwynedd, Wales On the A496 coast road.
England
Durham Castle Palace Green, Duram, England In the city center, adjacent to the cathedral.
Tower of London London, London, England Tube station: Tower Hill on Circle/District Line. Monument on Northern Line. Docklands Light Railway: Tower Gateway Station.