Here is another great thrifty find. It's called "How to Measure". This box contains several different cards with various pictures on them, as well as a whole bunch of 2cm plastic cubes.
The object is to place the cubes along side the picture on the card and see how long, tall or wide each object is.
On the other side of the card you can compare other household items to see if they are the same size as the picture on the front.
Quite the interesting measuring lesson.