Over the past 2 weeks our KS3 students have been doing their Commonly Assessed Tasks (CATs). These tasks involve students working through a Mathematical investigation such as the 'T-Totals' investigation.
In order to break down the lessons whilst students work through these tasks I have used the website www.simonscat.com - a website I saw a tweet about not long ago and felt it provided a useful 'breather' for my students at the end/start of lessons whilst working independently through their investigations. It also provides the minutest of links to their CATs!
Check the site out now - the videos (films) http://www.simonscat.com/Films/ are only around a minute long each and are rather amusing, especially if you have a class full of cat lovers!