Strictly pedagogical

Not an app but close enough - love it.

In addition to using Lego for maths, I've taken my sons (extensive) Lego collection into History and Society & Culture to have the students (high school) demonstrate their understanding of concepts such as globalisation, communism, nationalism, capitalism. Worked really well and classes sooo happy. 

Having been broken up into groups and given a concept each, They created cities or environments demonstrating the concept then talked the rest of the class through. 

Fantastic ideas for using lego in mathematics. Simple hands on tasks.