After 18 seasons and 400 episodes, Fox's The Simpsons (Sundays at 8 pm/ET) has attracted more than 350 celebrities to offer their voices to animated doppelgangers. Some have played themselves (Steve Buscemi, anyone?), some new characters (Reese Witherspoon as Rainier Wolfcastle's daughter, for instance), some old characters (Kiefer Sutherland and Mary Lynn Rajskub, who reprise their roles from 24 on May 20) — and in one instance, a mix (Elizabeth Taylor played herself and voiced Maggie's first word). Throughout, producers have attracted big (and not-so-big) names from many walks of life, from academics (Nobel laureate Dudley Herschbach, Stephen Hawking) to sports (Mark McGwire, Gerry Cooney, Joe Namath). We decided to pick three disciplines — television, film and music — and rank our favorite appearances, from "Simpsons Roasting on an Open Fire" (the de facto pilot) up to last week's episode.
Voices from TV:
1. Johnny Carson. When The Tonight Show mainstay announced his retirement, he left the door open for more TV gigs down the line. But aside from a few talk-show guest stints, his only real comedic role was in 1993's "Krusty Gets Kancelled," the fourth-season finale. Carson played himself — or rather, a superhuman variation of himself, who can dance on a table while spinning an automobile in his hands.
2. David Hyde Pierce. Kelsey Grammer got one of the juicier recurring guest spots with Sideshow Bob, but the Frasier alums were united in cartoon form for 1997's "Brother from Another Series" episode, with Pierce playing Bob's jealous brother Cecil. A great in-joke comes when Bart asks Cecil to guess who: "Maris?" he ventures, naming Niles Crane's never-seen wife.
3. Jim Forbes. Don't recognize the name? Well, you'd recognize the voice. Forbes' distinctive narrative style got him through more than 100 episodes of VH1's Behind the Music series. Forbes offered that same dramatic portend when he narrated the hilarious parody "Behind the Laughter," which closed out the 2001 season (and won The Simpsons another Emmy).
4. Dennis Weaver. Weaver was already part of television history from his involvement with Gunsmoke — at 20 years, television's longest-running prime-time series (and nearly threatened by The Simpsons, which enters its 19th season in the fall). But Weaver got to flex his comic skills in "The Lastest Gun in the West," playing Buck McCoy, a has-been B-movie Western star. Weaver mocked his image while simultaneously delivering a great vocal performance.
5. Tracey Ullman. It's fitting that since The Simpsons got its start as a series of shorts on The Tracey Ullman Show, that show's leading player would show up as a voice on the phenomenon she helped spawn. Ullman appeared in an early episode, "Bart's Dog Gets an F," as Emily Winthrop, a demanding dog-school trainer. When Santa's Little Helper finally proves his worth by rolling over and sitting up, she gets to exclaim, ironically and accurately, "Son of a bitch!"
Voices from Film:
1. Meryl Streep. She may be called the greatest screen actress of all time, but Streep couldn't say she'd really "made it" in popular culture until she showed up on The Simpsons, playing Bart's evil love interest on "Bart's Girlfriend" in Season 6. As Rev. Lovejoy's incorrigible daughter, Streep got to be her most wicked character until The Devil Wears Prada.
2. Dustin Hoffman. Don't recall seeing his name in the closing credits? Maybe you should have been looking for "Sam Etic," the pseudonym Hoffman used for his role as Lisa's inspirational teacher. Maybe because the episode came in Season 2 — still early in the show's run — Hoffman thought better of associating himself with a cartoon, but now he's one of a handful of celebs who didn't lend their real names to the show. Still, his "Mrs. Krabappel, you're trying to seduce me" line unmistakably marked The Graduate star.
3. John Waters. Moviedom's most notorious cult-film director got to play a family-friendly version of himself on "Homer's Phobia" in 1997. Waters was John, an openly gay resident of Springfield (and apparent some-time paramour of Mr. Smithers) whose influence on Bart make Homer worried his son may turn out gay. "I like my beer cold, my TV loud and my homosexuals flaming!" Homer proudly declares — until John saves his life.
4. Susan Sarandon. The same year Sarandon appeared in her Oscar-winning role in Dead Man Walking, she played Bart's Russian ballet teacher in "Homer vs. Patty and Selma," showing off her comic timing.
5. Pierce Brosnan. The smoothly sophisticated Brosnan did a send-up of his James Bond image by playing the voice of the Simpsons' new high-tech house — one with a murderous streak — in the 2001 Halloween episode.
Voices from Music:
1. Bette Midler. The pop singer appeared in a variation of her own Emmy-winning appearance on The Tonight Show alongside Johnny Carson.
2. 'N Sync. The fivesome did a send-up of their boy-band image by teaching Bart and company how to be fluffy and superficial in the hilarious spoof "New Kids on the Blecch."
3. The Rolling Stones. Mick Jagger and Keith Richards play themselves as buttoned-down instructors at a rock-and-roll fantasy camp in "How I Spent My Strummer Vacation."
4. R.E.M. The rockers from Athens, Georgia, get tricked into playing a gig in Homer's garage — but forgive him with a tofurkey dinner — in the "Homer the Moe" episode in 2001.
5. Tony Bennett. Popular music's reigning living legend appeared twice, with more than 10 years between episodes — singing about Capital City in "Dancin' Homer" in 1990, then again in 2002's "Bart vs. Lisa vs. the Second Grade."
And TV Guide's All-time Favorite Guest Voices:
1. Marcia Wallace. The only reason the voice of Bart's teacher, Mrs. Krabappel, wasn't listed, Jean assures us, is that he doesn't consider Wallace a guest at all, but one of the regular cast members. And with more than 115 appearances, we see his point.
2. Harvey Fierstein. One of the earliest notable guests was the gravel-voiced actor, playing Karl, Homer's executive assistant who is secretly in love with TV's most famously homophobic family man.
3. Pierce Brosnan. 007 became HAL 9000 when he spoofed his image as a suave sophisticate by appearing as the homicidal voice of a computerized house in a classic "Treehouse of Terror Halloween" episode.
4. Jane Kaczmarek. The Malcolm in the Middle star debuted in Season 13 as the hard-edged Judge Constance Harm and continues to rule from the bench with a dark-hearted fury that would bring a smile to Karl Rove's face.
5. The intelligentsia. What show but The Simpsons would consider poet laureate Robert Pinsky, astrophysicist Stephen Hawking, and novelists like Gore Vidal, Jonathan Franzen, Amy Tan and Michael Chabon and give them collectively more one-liners than in all their work combined?
Let our Online Video Guide 'toon in some Simpsons clips for you.
Send your comments on this feature to email@example.com.