This was Greg and Rowley's Holiday Bazaar they made in Cabin Fever. They advertised it through their newspaper, The Neighbourhood Tattler. They planned on making it a fun place by getting stash of Drummies and making homemade arcade games.
They also planned an arcade with gaming machines. But the arcade machines were expensive, so they just tried to make ones with cardboard. First they tried Pac Man, with the idea that they will get ice-cream sticks and paste pictures of Pac Man and the ghosts on them, then the player would control Pac Man while Rowley operated the ghosts. However their maze fell into the cardboard machine after being made. So they scrapped the idea and made the idea of Rowley being in the box instead.
They also wanted to sell cheaper Drummies so Greg started buying up the stash of the grocery store. Soon they put an advertisement about their bazaar in their newspaper. It was unknown if they actually managed to sell them or not.
School Wall Vandalism
When Greg and Rowley completed doing every thing, they made advertisement posters. It was raining when they reached the school walls, they put up the posters. But the rain washed out the ink and the poster started messing up, so they started taking them out. But just then someone saw them from far away and shouted at them. Greg and Rowley took the posters off quickly, but the posters bled causing splotches on the wall. They escaped without being recognized. However in the newspaper there was news that two vandals defaced the school walls. It was trending all over the school, so Greg told Rowley to wait until it all ends. But Rowley was scared, because he thought he might not be able to get a job in future due to this. However, Rowley wrote a no-signature note which read "me and Greg Heffley vandalized the school." After reading this, Vice Principal Roy called Greg to name his companion, however Greg didn't name and took the blame to himself and cleaned the walls after school.