11. 25 Years And They Can't Come Up With A New Punishment (Season 25, Episode 1 - Homerland)
It's all-too apt that this episode's chalkboard gag talks about the issue of punishment considering that the central plot is a spoof of the popular Fox spy show Homeland. More comically, it's also a jab at the fact that the chalkboard gag is this relic which has somehow endured over the years, even though in reality the school's teachers would surely have sought other punishments for Bart after all this time. Then again, perhaps the staff at Springfield Elementary are just that terrible...