There are stretches of my day when there is really nothing to do except wait around. This happens at the Post Office, or when I’m waiting in line at the pharmacy to pick up a prescription, or just standing on a subway platform waiting for the A train.
Recently I have gotten into the habit of using those opportunities to memorize stuff. I will load something on my phone, maybe a favorite poem, or the lyrics to a song I like, or some particularly awesome speech from a Shakespeare play.
And then I will practice silently, aiming to get the words exactly right, going through the work in question until I can say it perfectly without looking at my phone. And for any given poem or speech or lyric, I will continue doing that for a few days afterward just to make sure I’ve got it nailed down.
I can’t say with certainty that this is the best possible use of my time. But it has turned out to be an extremely pleasant little hobby.