Three weeks in and those celebrities are still putting their brains to the test. This week host Alexander Armstrong and fountain of knowledge Richard Osman put the likes of former athlete Colin Jackson and Casualty star Suzanne Packer to the test, Can they find the most obscure answer? You'll have to wait and see. If you find yourself really getting into it then don't touch that dial because Clare Balding will be setting some pretty interesting challenges for Britain's Brightest at 7pm. It's all or nothing with the last place in the final up for grabs.