If I have nothing prepped, it’s goofy random sidequest night.

One of my favourite sessions ever started when the player the session was focused on called out due to work. With my plans derailed I had ninjas crash through the window, steal her famous recipe book, then run off and leap into the back of a van with her biggest rival at the wheel. It turned into a driving battle on the highway with characters leaping from vehicle to vehicle while a supervillain chef pelted them with capsaicin-laced muffins. It ended with an elderly PC duking it out with a morbidly obese NPC (neither of which had any points in fighting) in front of a police station. They traded single points of damage until the cops finished laughing and arrested them both.