Commented on Ask HN: How do you spend your free time in office? via Hacker News:
Researching ideas that previously came to my mind minutes before when I was busier. I write down these kinds of ideas to save them for later and them I put them out of my mind as I'm trying to do my work. Or, I just browse HN.
Usually I look at this through my phone as I'm walking somewhere. Taking a 4-5 minute break for a walk is important because sitting all day is not healthy. Sometimes the walk has a purpose such as going to the coffee machine. Sometimes it's just randomly moving around then go back to my seat.