ETA: Thanks to spotts1701, we know that it's another week wherein the Pattersons prove that they can't cope with ordinary life.
Panel 1: As our story begins, it's another weekend afternoon at the Pattermanse. We see Mike smiling as he bends a water hose.
Panel 2: He looks over the corner.....
Panel 3: ....and lets the hose go.
Panel 4: We next see John get blasted in the face by the sprinkler because he was too dim to check the tap.
Summary: If the joke had been current at the time, someone would probably have told Lynn that Hank Ketcham just phoned and he wanted his punchline back. It's amazing how derivative she used to be, ain't it? Also, we know what Panel 5 would have been given John's temper: "John paddles Mike's behind because he got outwitted."