How do I record TV shows?

Yes, https://www.tivo.com/shop/promo/roamio requires a US$15/mo. subscription. It might still be worth considering, since it seems to be much simpler to set up and use than the other options I've seen. Personally, I record digital broadcast TV by connecting my antenna to an http://www.hdhomerun.com/, which is connected through my home network to a small Linux computer that lives under my TV and runs http://www.mythtv.org/, a free, open-source DVR program. MythTV is very flexible and once it's running it's very nice and easy to use, but getting it installed and configured is frankly a major pain. I also pay $25/year to http://www.schedulesdirect.org/ for better-quality schedule listings than the ones that the networks send over the air. If you want something with potentially less fuss, I'd buy a https://en.wikipedia.org/wiki/Windows_Media_Center with either a built-in TV tuner or an HDHomeRun. There are also http://www.amazon.com/exec/obidos/ASIN/B004XIB9UA/metafilter-20/ref=nosim/ that are cheaper and possibly easier to set up since they have everything in one box. The ones I've seen have mediocre reviews when it comes to features and ease of use, but if your needs are simple then this might be the best bet.

The http://www.channelmaster.com/Products_s/329.htm doesn't require a subscription, is nice-looking, and http://www.amazon.com/exec/obidos/ASIN/B00JGZQ17Q/metafilter-20/ref=nosim/. It does need an external USB HD to record shows on, though.

Assuming you already have a connection from your computer to your TV, you can try something like this http://store.hauppauge.com/hardware2.asp?product=hvr950_mac_pc that allows you to record HDTV on your computer. No subscriptions needed.

I get that you don't want to include your computer in this setup, but involving a computer may still be the simplest, cheapest route. https://www.youtube.com/watch?v=AqLhNQ4OhGE.

You want to search for PVR (personal video recorder) instead of DVR. http://www.amazon.com/exec/obidos/ASIN/B00GGVPKKC/metafilter-20/ref=nosim/ is reasonably priced and reasonably well-reviewed (you do need to supply a USB drive for storage). I'm not 100% sure what your setup is of course, and whether this will work with it.

http://ask.metafilter.com/262199/How-do-I-record-TV-shows#3808387: "but the reviews for the SimpleTV make it sound like it can be a headache to set up" It can be simple, but can easily go awry. But tweeting them got me a resolution within a day and once it was set up, i've had no problems.

Thanks, O9scar, for the term "PVR." That did bring up a lot more choices including the SimpleTV. I do have a Roku box, but the reviews for the SimpleTV make it sound like it can be a headache to set up. Those other pvr tuner/recorders, look pretty neat, though.

Haven't used one, but SimpleTV is probably what you're looking for. I have and use Windows Media Center, but it's fussy because it's a computer.

I use a http://www.amazon.com/exec/obidos/ASIN/B00BF2M21C/metafilter-20/ref=nosim/ that I bought through Woot!. You need to supply an external hard drive - and you need a Roku if you want to watch on your TV (instead of on your computer). But it works reasonably well and works for my simple OTA PVR needs.