We played with geometric shapes, and maths turned fun and interactive as a result.
Shapes are usually a child's first encounter with geometry, and it is best if that encounter happens through the hands rather than through a definition. A square drawn on the board stays a drawing; one you fit, turn and compare with another becomes an object with properties: its sides are equal, it fits here, it does not fit there.
From here you go on, later, to far more serious things — area, symmetry, the way a complicated figure breaks down into simple ones. But the beginning stays the same: seeing shapes around you, not only on a worksheet.