Based on my favourite joke from "Bart of Darkness".
One of the few things that helped Bob endure the torment of being Krusty's sidekick was the patient wait for the magic words Krusty would say every year in late May or early June:
"I hope you enjoyed that, kids, because Krusty is OUTTA here for the summer!"
The flashing sign in front of the young audience would indicate that they were supposed to give a disappointed "Awww", something Bob didn't care for. The children weren't stupid; they didn't need some pathetic clown telling them how they ought to feel.
"Yeah, yeah, I know," Krusty would say. "But in the meantime, we'll be airing...Classic Krusty." Krusty's voice always had obvious contempt in it when he spoke of his old shows, but most ironically, the earliest black-and-white episodes of Krusty's show felt funnier to Bob than the newer stuff. It was something to do with the fact that a clown was discussing serious issues. The children may have hated those episodes as much as Krusty, but hopefully Classic Krusty gave them a reason to spend their summer vacations playing outside, instead of lounging in front of the TV until their fragile little brains decayed like a tooth that never got brushed properly.
Krusty would laugh nervously and declare, "Enjoy!"
That was always Bob's cue to get the hell out of that studio. He'd have a nice hot bath to soothe his aching muscles, and then drink some tea. And on some days (though Bob would never admit this to anyone) he'd relax in his armchair and watch Classic Krusty, because it entertained him to watch the Sideshows who had preceded him, and show him he wasn't so alone in his suffering. Not a bad way to pass the time: just him, his chair, a cup of tea, and watching painful slapstick antics that weren't hurting him for once.