The Soma cube is a 3D puzzle that consists of 7 pieces of different shapes. These pieces must be assembled into a 3x3x3 cube. There are 240 distinct ways to solve the puzzle. I made a home-made Soma cube puzzle out of small, about 1.5 x 1.5 x 1.5 cm (9/16 x 9/16 x 9/16 inches) colored wooden cubes, like those you can buy at arts and crafts shops. I didn't have to buy them, since we have been using such cubes for a long time — the kids like playing with them. Only 27 cubes in total are needed. I just glued them together with a wood glue, and here we go: now my children can enjoy this amazing puzzle, they solve it or build various 3D shapes out of its pieces: castles, animals, etc.
Some interesting resources about the Soma cube: Soma cube in Wikipedia, Soma cubes, and a lot of stuff on the Soma cube.