Our recent extracurricular math activities have brought out the linking cubes. We haven't used these in a very long time. I found an activity book that I'd forgotten about and Robbie is having fun doing an activity or two each day or so.
Here is a look at a bit of his work on symmetry with linking cubes.
He also wanted to do this puzzle. Unfortunately, I was unable to locate three of our linking cube colors (30 cubes) until later in the week, so he was only able to get so far.
This is the book we've been playing with (there is also one available for grades 3-6)..
.. and these are the cubes we have..
Check out other (and admittedly, much cooler) math ideas over at