My company is going out of office for 8 hours; I have no work left to do. What do I do?

I don’t have any work to do currently. My company has a mandatory team event today, which is going out of the office for a few hours. I am a web developer, so all of my work is on the computer. I’m genuinely unsure about what to do. I’ve never been in a situation where I don’t have any work to do left and my company is making sure I’m not in the office.