Celebrities including actors James McAvoy and Chris O'Dowd, DJ Edith Bowman and author Michael Morpurgo explain their love of books. Barney Harwood also gets an insight into this year's 500 Words story-writing competition. Plus, scientist Greg Foot reveals the secrets behind electricity.

After weeks of hard training it’s the final part of Lindsey Russell’s Mountain Marathon challenge. Will she manage to complete the 35-mile race across glaciers and skiing down the Swiss Alps?

Barney and Radzi go head to head in a synchronised swimming challenge, and the team are in the garden with Greg Foot to look at the science of extreme bike riding.

Morph creator Peter Lord joins the team in the studio, Lindsey paints a giant ship, and Radzi looks into the court-line technology used at the Wimbledon tennis championships.

Lindsey and Radzi go head to head in a cricket challenge at Lords with England cricket stars Jamie and Craig Overton. Also, the team get tips from internet super-vlogger Zoella.

The team are live on the road to celebrate the start of the summer. Radzi and Barney take on a challenge on homemade go-karts and Lindsey learns the art of the flying trapeze.

Blue Peter continues the mission to find CBBC Intelligence Officers. Over 5000 viewers applied but only three get the chance to go inside MI5's Headquarters.

With Christmas just around the corner, Lindsey and Radzi go head to head in an ice-sculpting challenge. The team take a look back at some moments from the past year.