Minecraft modding has done so much to get young people into CS. I started learning Java when I was 10 because I wanted to do modding. At university, I met so many people who had the same experience. The tooling developed for Minecraft modding is world-class and better than what is developed during PhDs. It's very advanced, and people internalized the JVM and Java spec. One problem, though, is that Mojang's updates often change much of the foundation, and upgrading mods is very time-intensive. Mojang announced in 2012 that an official modding API is in the works. This is another step.