Web site editor. Of all side hustles it is probably the lowest overhead for the $/hour you can earn. My day job is so web focused that I try to not take on many web side jobs, preferring to focus my evenings on more crafty side hustles (I have a full on garment design business, but that wasn't free to start up) However, I charge $50/hr for basic html edits, $100/hr for each page I build for a customer. $100/hour for graphic design. As far as TV watching while coding, that is not likely too relaxing, but simple edits of web page HTML would be doable I think.
Lets see, thinking outside the box, if you have internet and a PC, another fun possibility would be to learn to code phone apps. That is something I would like to dig into some day - likely well past the time when boatloads of money can be made:) Your earnings would be the sales of your apps you post. again, Not quite as easy to split your time watching TV while coding. I can see the need to rewind alot here!