I maintain a part-time programming job and a seasonal farming job. That provides a reasonably stable income without dominating all my time. Then, it's just picking up whatever my desires at that time take me to, which could be on a freelance basis or even turning the interest into a product for sale.

I have become especially fond of the latter approach, when possible. No million dollar moonshots like you often read about around here, but I've had good luck at least making back the cost of my time/materials, which is quite gratifying for something I'd tinker with for free in my spare time anyway.

I think it works really well for me. I love the flexibility and variety while still being practical. But, again, I have been fortunate to be almost exclusively interested in things that people are willing to pay for.