In Emerald changing the "Trendy Phase" to "Adult Anime". Everyone in Dewford Town now has a Hentai fetish.
Slowflake Reads Metroid High. All of it. The fun is not just in the terrible fanfic, but also in Slow's reactions.
Super Mario Star Road gives us the glitchy Chill Bully shenanigans. Every time Slow kicks it off the platform, it ends up stuck somewhere he can't possibly kill it, or it attacks him before he's even on the platform. At the end of part 14, it finally looks like he's succeeded... And then we see it's happened again. Part 15 turns it into a Brick Joke, when we see that the Chill Bully ended up at the location of a star he decided to go after instead. And then the game finally takes pity on him and lets him kill the thing.