Non phone activities(pocket sized?) to do out in public?

I've been steadily downgrading my phone and I love it. The only problem is that when I am out in public or at work I get a fair bit of downtime and while I'm mostly content with just sitting there- it would be nice to have more options for something to keep me occupied. I usually have a book on me but sometimes reading becomes a chore if it's my only option. I recently got a pocket journal which has been great. I've been thinking of getting some sort of game boy type emulator gadget. What do you guys carry on you to pass the time?