Cross stitch
I like cross stitch because it doesn't take a lot of brain power. It's essentially painting-by-numbers, but with string. I do a lot of it while watching TV or listening to podcasts.
Most of the time I stitch other people's designs, but I have designed a few of my own when I couldn't find something specific.
My finished pieces are almost all framed and hung on the wall leading up the stairs in my house.