In clinic breath test - what was your experience

Anyone have any tips on how to pass the time? For those that don’t know, I’ll be there for 3 hours breathing into a tube every 20 min. I’m going in 2 days (tomorrow’s the big bland food day) and I’m a bit anxious about the amount of time I’ll need to be there. I plan on bringing my laptop and my switch but I’m curious to hear what others have experienced during the test and what they did to pass the time!