http://www.nrich.maths.org.uk/
A really rich resource, for extending students, with new activities each month; use the Archive to find activities and solutions from previous months
http://www.bbc.co.uk/cbeebies
Activities and games based on CBeebies characters such as the Teletubbies, Fimbles, Tweenies and Bob the Builder. Aimed at ages up to 6.
http://www.bbc.co.uk/schools/digger/
Digger and the Gang activities to support Year 3 and 4 of the National Strategies for Literacy and Numeracy, and KS1 and KS2 programmes of study
http://www.bbc.co.uk/schools/laac/menu.shtml The Little Animals Activity Centre can be used as part of the literacy hour and daily maths lesson for reception year and years 1,2 and 3.