Ok so it's not exactly on the doorstep, but i've heard some good things about Magna Science Adventure Centre in Rotherham. It's the kind of place that kids will spend a field trip at, but it's got plenty of handz-on science stuff for younger kids too.
On Wednesday 28th May, they're having a ‘Colour Day’ to celebrate their latest exhibition, Eye for Colour, which explores things which are bright and colourful. As an added incentive Children who wear red on this day will get in for free.
I, for one, love stuff like this, cos all too soon children get soooo over dresssing up, so make the most of it while they can't protest!