(I posted this in the MST3K thread but it seemed appropriate here as well)
Roku has added something called PLUTO TV. It's free. It's a collection of a bunch of unique channels, including a streaming MST3K Channel and RIFFTRAX Channel. Other channels include comedy, reality, news, movies, etc. It's like variations of those free channels like ANTENNA and COMET that started popping up a few years ago.
I like the MST3K and RIFFTRAX services, since they play content continually, so I can leave it on as background noise and not feel too guilty about not paying 100% attention.
Here's the PLUTO TV website. I guess it's available to other non-Roku devices as well.
Here's their current listing of channels.