given notice that the Paternoster Gang are returning - they're asking their viewership (i.e, people between the ages of six and fifteen only) to create sonic devices for Strax, Vastra, and Jenny. These will then be incorporated into a proper broadcast episode at some point. The winner gets a set visit to watch their creations in action.
The press release has a little info about their plans for the big day in November: "On Thursday 21 November and Saturday 23 November, Barney, Lindsey and Radzi will be joined by aliens and monsters in the studio and the audience will be able to design their very own alien live on air. Blue Peter viewers will have their questions answered by Matt Smith; they will be able to get ready for the 50th anniversary show by making their very own cushion (to hide behind); and we’ll help them to host a Doctor Who party by showing them how to make Dalek cupcakes."