This is such a hard list to do, mainly because there’s so much damn source to pull from, but I’ll try to wing it by doing my favorite episode of my 10 favorite shows, and then ranking those
The Simpsons: Last Exit To Springfield - the absolute perfect Simpsons episode.
30 Rock: MILF Island - first of all, we get a whole episode of MILF Island! Secondly, the meta humor of the characters of 30 Rock participating in reality show-type plot and not even realizing it!
Futurama: Fear of a Bot Planet - I remember the first time I watched this episode, I thought “holy crap this is the funniest half hour of TV I’ve EVER seen.”
24: 11:00 p.m.-12:00 a.m. - the one where people die, stuff blows up, and the friend turns evil.
Lost: Man of Science, Man of Faith - pretty much the biggest mind-fuck episode ever. Plus the introduction of Desmond!
Firefly: Out of Gas - such a tragedy this show didn’t last longer. This episode got me hooked more than the pilot did, with a great adventure story.
Seinfeld: The Bottle Deposit - an episode that is probably taken for granted nowadays, mainly cuz we’ve seen it so many times, but there is an INCREDIBLE amount of humor crammed into this episode!
The Shield: Pilot - this show didn’t waste any time establishing that this was gonna be a NEW kind of cop drama. Not only had the great Dutch story with the pedo who is trying to trade kids, but the episode ends with the main star, the big cop, murdering one of his partners!
South Park: Chinpokemon - it’s been like 10 years and I’m STILL quoting this episode!
Law & Order SVU: Ghost - Casey Novak AND Alex Cabot together for one hot episode. Sorry, but this show is all about the hottie lawyers.