At the turn of the year I started freelance writing on Economics with a company called Shmoop. It turns out that writing, even about something you like, can be exhausting. I can't believe how hard my brain has been working since I started, mostly trying to remember all the knowledge hiding under 13 years of cruft. And even though I've kept my hand in, the basic 101 concepts are hard to put in a simple form, without overwhelming the reader with other stuff that maybe they haven't learned yet.
This is part of my 2016 'year of the gig economy' that I am living, where I cobble together a living from odd jobs. I'll tell you in 2017 how it worked out, but right now I'd say it doesn't pay all that well.