somea puzzles
The pieces of this puzzle can be put together to form a cube  it is called the Soma Cube. Here is a page that shows the 7 parts that make up the soma cube in 3D.
You can buy the wooden version of this shown here from educationinteractive (along with lots of other nice maths things), or purchase a different (plastic) version called 'Blockbyblock' that contains 60 shapes to try and make  some of them are not easy! 
On the right is a video of one of my year 7 students completing it in super quick time! I decided to make a huge one out of cardboard boxes (inspired by George Hart). Below is a slide show of various students and teachers getting to grips with the boxes (click to play), and here is a video of the year 12 students enjoying what they made! The teachers tried to solve the soma cube as part of a staff conference session I ran called 'play and talk'. 

Through the momath website I also found out about the puzzle tetraxis, shown below.
Thanks to Jane Kostick for being so helpful in discussing the tetraxis; she tells me they are not making any more because the cost of magnets has increased so dramatically this year! She sent me this is a really interesting description of the geometry behind the tetraxis.