I work on programming projects I find fun. What makes it recreation is that it's something I want to work on, I don't have others imposing deadlines or requirements.

A mechanic can enjoy working on his own project car in the off time.

Both of these things are productive in a way that playing games isn't, but they're still recreational. It's not spending your life chasing dimes. It's looking at the different recreational things you could be doing, and choosing the ones that also intersect with being productive and have a side-effect of helping you professionally.