Has there ever been an episode of The Simpsons that didn't include all five of the core Simpsons (Marge, Homer, Bart, Lisa and Maggie)?
I like to think of myself as a quite a bit of a Simpsons nut, but when my wife sprung this question on me, I sat and racked my brain for hours, trying to think of the answer. I even went through the plot synopsis for the first 17 seasons, trying to think.
The closest I could come up with, was a Halloween special, or that Maggie or Lisa weren't in it due to the episode being a Bart / Homer heavy one (and the Spinoff Showcase doesn't count, as Lisa was in the previous skits with Chief Wiggum etc.)