When our son was very small, we gave him real tools, sized to fit tiny hands - they're still useful today. When he was 11, he made his own tool box to keep them in. He, like both his parents, is a tool addict.
At 5, he got his first computer, and I showed him how to do simple programming; at 16, he was a certified MicroSoft instructor, teaching people twice his age. He runs an IT department now (using as little MS product as possible!), and does a fair amount of diy.