If you and your kids like History, then check out Museum of London’s teacher resources.
The site has online and printable resources on Prehistoric London (500,000BC to 43AD), Roman London (43-410AD), Anglo-Saxon, Viking, Medieval and Tudor London (410AD-1558), Stuart, Commonwealth and Hanoverian London (1558-1837), Victorian and Edwardian London (1837-1913), First and Second World War (1914-1945), Postwar to the present (1946-) and London’s Black history.
Ah… freebies… gotta love ’em. :)