A video game where the whole concept is that you're in a city, and you've got a pressure washer. You can pressure wash anything. Just pick a random object, wall, car, pavement, statue, go "hmm, I wonder what colour that thing used to be?" and then you just run the washer over it, slowly and neatly and not missing a spot, very calm, very soothing, very relaxing. If you aim it at people, they get mad at you. If you aim it on squirrels or very small dogs they explode. People don't like that either. If enough people get mad at you, the cops will start chasing you. You're fine for as long as they don't catch you. If you find a good hiding spot, they give up looking for you eventually. You can pull up a manhole cover and hide in the sewer. Chilling there for a bit. Pressure washing the walls. Pssshooooom.