I am a fan of mazes and puzzles, that's why I loved the Curvahedra by Edmund Harriss. It's a Kickstarter project where you can make this Curvahedron ball!
CURVAHEDRA is a playful and flexible geometrical construction system, laser-cut out of thin card.
The flat pieces of card link together in an ingenious way, without the need for glue or tape, to build an array of 3D structures. With the your creative power, numerous spheres, cones, and even more elaborate forms, can be made.