Together with his daughter Karina Bik, Aart enjoys building robots with Lego Mindstorms. He also volunteered as a teacher for a Mindstorms robotics course in a Sunnyvale highschool. Below you see some pictures of robots built with Lego Mindstorms EV3 (the latest) and Lego Mindstorms NXT (first generation).
Fun Mindstorms Lego Mindstorms EV3 starter robots are the TRACK3ER and the R3PTAR. The ROV3R is a nice general-purpose robot, taken from the EV3 Laboratory book. Fun Lego Mindstorms NXT projects are the tribot, the alpharex, and the robotic arm. Of own design are the catapult and the gears project (used in the highschool course).