Arduino has a nice simplified C language and a friendly and simple IDE. I recommend skipping the Basic Stamp.
Other than that, bare-metal programming on microcontrollers has the advantage that the boy can get a mental picture of the entire machine in his head; not so easy with an SDK of hundreds of megabytes for a modern high-level language.
Other than that, bare-metal programming on microcontrollers has the advantage that the boy can get a mental picture of the entire machine in his head; not so easy with an SDK of hundreds of megabytes for a modern high-level language.