Use the text "How to design programs" and Scheme. It's been used in high schools, is quite approachable, and is easily motivated by connection to recurrence relations, which seem to be a theme in my 14 year old's math curriculum. The book is free on the web, and the programming environment is also free and supported on many popular platforms.

We used to call these "Kenner sets". The best was the "chemical plant" one, which had tanks, pipes, valves, and a pair of reservoirs with motorized pumps. You could build (simulated) oil refineries! The highway and skyscraper sets were pretty good, too. You could build huge suspension bridges with the sets, and they were pretty close to HO scale so you could integrate them into a train layout.