1. Crispin Glover on Letterman (1987)
Let's start with Courtney Peldon's ex-boyfriend (they started dating after this though because she was in the first grade when this originally aired). A woman in the audience heckles Crispin, and I am fairly confident she was not a plant.
2. Drew Barrymore on Letterman (1995)
This is the one where Drew got on a table and flashed Letterman for his birthday. She said she usually spends her birthdays crying in a bathtub.
3. Madonna on Letterman (1994)
It didn't start well. Madonna said she was only there bc the Knicks weren't playing. Letterman asked her to a kiss a guy in the audience, which is gross like wtf. Then Madonna said, "incidentally, you're a sick fuck." She had apparently given him a pair of her panties before the show and asked Letterman if he wanted to smell her panties and also said peeing on your feet in the shower is good for athlete's feet. In a handwritten letter -- that was auctioned off in 2018 and was valued at $2000 (idk how much it sold for) -- Madonna wrote to her fan club two months after the appearance, she said:
Can everyone please get over the fact that I went on t.v., smoked a cigar, said the f-word a few times, and made David Lettermen (sic) look stupid. I actually had a very good time, thought it was one of my better performances and proved once again how sexist the world we live in really is.
If I were Andrew Dice Clay or Snoop Doggy Dog no one would have given a f---!. In this country you are not allowed to be a girl, look good, have a point of view and have a good time all at once. need I say more?
She also wrote to her fans that everyone should have a rose garden and recommended snackwells cookies. You can read the entire letter at the auction site.
4. Any Joaquin Phoenix interview but this David Letterman one in particular (2010)
This one isn't so much iconic as it is memorable. This was circa Joaquin's collab with noted sexual harasser Casey Affleck. Idk maybe he was ripping off Madonna but he flopped. Hard.
5. Harmony Korine on Letterman (1998)
This is Korine's third and final appearance on Letterman. He was high on shrooms and was banned for digging around in Meryl Streep's purse.
6. Sean Young on Joan Rivers (1991)
Sean Young really wanted to be Catwoman in Batman Returns. Real bad. She Appears in costume and helps Joan open a bag of kitty litter, and then Joan pours it all over her chair and sits in it. She was going to be in the first Michael Keaton Batman movie, but she fell off a horse during rehearsals and was replaced by Kim Basinger. Tim Burton wouldn't even take a meeting with her, so she's justified but the cat toys and costume were a bit much.
Bonus: this is the entire episode. Enjoy the vintage ads. Make Sure to check out the 1-800-MD-TUSCH ad. That fix your hemorrhoids jingle is a must listen!!