Acroban is a lightweight compliant humanoïd robot. It is capable of semi-passive dynamic movement, including semi-passive dynamic walking. Equipped with a multi-articulated vertebral column, its bio-inspired design relies heavily on the use of adequate morphology and materials for robustness and adaptivity to external perturbations. This allows not only for advanced motor skills, but also affords a new kind of physical human-robot interaction which is made possible by the ability of the human to modify the state (joint positions) of the robot by a direct physical manipulation, thanks to compliance. In this way, joints become the interface between the robot and the human. Especially the interaction between the children and the robot near the end is quite fascinating.