Programming definitely, also, if you get into it, there is a game called screeps, it is on steam.
In short, simplistic graphics, real time strategy, buildings units and everything is run by your own code, so you make code that will repeat mine this mine that build this here attack there make this unit upgrade that, it is very fun and fun is the best way to learn stuff.
It is not really for starts but it is definitely great for people that knows a slight part of coding and just wanna remember it and make it bonded into your mind.