Who: Morris "Moe" Lester Szyslak

Voiced By: Christopher Collins, Hank Azaria

Introduced: "Simpsons Roasting on an Open Fire" (episode 7G08, Dec. 17, 1989), which was so funny that we videotaped it -- which was like TiVo-ing back in the Stone Age -- because we feared that it would never be seen again

Best Episode: "Homer the Moe" (episode CABF20, Nov. 18, 2001) in which Moe redecorates the bar, making it a cool hip joint, and utters the immortal line, "Nobody calls Moe St. Cool a phony!"

Fun Fact: Before being the voice of Moe in the episodes "Some Enchanted Evening" and "Homer's Odyssey," Collins -- who died in 1994 -- was best known as the voice of Cobra Commander on "G.I. Joe." Before taking over as the voice of Moe, Azaria, who now also does "Simpsons" characters such as Apu, Bumblebee Man and Dr. Nick Riviera, did an episode of "Family Ties."

Why We Love Him: Because he can be as evil, and as funny, as Mr. Burns, while also lacking the internal censor that makes Homer so funny and, well, evil.

Who: Selma Bouvier-Terwilliger-Huntz-McClure-Stu

Voiced By: Julie Kavner

Introduced: "Simpsons Roasting on an Open Fire" (episode 7G08, Dec. 17, 1989)

Best Episode: "A Fish Called Selma" (episode 3F15, March 24, 1996) in which Selma married Troy McClure, who you might remember from somewhere

Fun Fact: Refused to marry Apu because her last name was long enough.

Why We Love Her: Because she's like an evil version of Marge -- but without the requisite goatee normally required of the evil versions of people.

Who: Krusty the Clown

Voiced By: Dan Castellaneta

Introduced: "The Tracy Ullman Show"-era short, "The Krusty the Clown Show"

Best Episode: "Bart the Fink" (episode 3F12, Feb. 11, 1996), in which Krusty tries to solve his tax problems by faking his own death. Twice.

Fun Fact: Among the many products that bear Krusty's name and likeness are Krusty Burger, Krusty-O's cereal, Krusty's Non-Narkotik Kough Syrup, the Lady Krusty Mustache Remover, Krusty-Brand Low-Income Housing and the Krusty-Brand Home Pregnancy Test ("Warning: May Cause Birth Defects.").

Why We Love Him: If you have to ask, you must be one of those weirdos who likes clowns.

Who: Robert "Sideshow Bob" Underdunk Terwilliger

Voiced By: Kelsey Grammer

Introduced: "The Telltale Head" (episode 7G07, Feb. 25, 1990), in which Bart steals the head from a statue of Springfield's founding father, Jebediah Obadiah Zachariah Jedediah Springfield

Best Episode: "Cape Feare" (episode 9F22, Oct. 7, 1993) in which Sideshow Bob's pursuit of Bart leads the family to enter the witness protection program and Homer gets a new chainsaw and hockey mask

Fun Fact: While incarcerated, Sideshow Bob's prison number -- 24601 -- is the same number as Jean Valjean in Victor Hugo's "Les Miserables." Even stranger, while incarcerated, Sideshow Bob is often miserable. Weird, huh?

Why We Love Him: Because many of the best "Simpsons" episodes -- including "Cape Feare," "Sideshow Bob Roberts" and "Krusty Got Busted" -- are Sideshow Bob episodes.

Who: Kodos

Voiced By: Dan Castellaneta

Introduced: "Treehouse of Horror" (episode 7F04, Oct. 25, 1990), which was the first of many "Simpsons" Halloween specials

Best Episode: The "Citizen Kang" segment of "Treehouse of Horror VII" (episode 4F07, Oct. 27, 1996) in which Kang and Kodos run for president, disguised as Bill Clinton and Bob Dole

Fun Fact: Kodos, oddly, has a deeper voice than her brother, Kang. Though it's still not as deep as Serak the Preparer's, which sounds kind of like a cross between Darth Vader and that guy who says "This Is CNN."

Why We Love Her: Because she is so much cooler than Kang.