List of billboard gags

Beginning in 2009, with the newly animated high definition Opening Sequence, came some new running gags that would change every week. One of these gags was before we see Bart writing something on the chalkboard, we would see a building in front of Springfield Elementary School with a billboard gag on top of it that would change every episode. These gags have not been reused at all, unlike chalkboard and couch gags. However, the billboard could also not be seen when the shorter opening sequence is shown.