1. Nelsan Ellis
Before he became Lafayette on True Blood, Nelsan Ellis played a refugee from Uganda in Season 3.
2. Paris Hilton
In an ambitious and surprising performance, Paris Hilton played a material girl obsessed with pink.
3. Amanda Seyfried
Throughout the first season, she was Lilly, Veronica’s dead best friend.
4. Melissa Leo
The Oscar-winning actress appeared in the show’s third episode as a transgender woman who left her son to undergo her transition.
5. Paul Rudd
Judd Apatow’s favorite actor made a cameo at the end of Season 3 as a disillusioned rock star.
6. Jane Lynch
She was one of the many teachers who disliked Veronica.
7. Adam Scott
He played a high school teacher accused of having impregnated one of his students…
8. Leighton Meester
And future Blair Waldorf was the student in question. It’s worth noting that back in the days, she was already considered the “gossip queen” of Neptune.
9. Jessica Chastain
At the beginning of Season 1, the Oscar nominee played the part of a woman abused by her stepdad.
10. Alyson Hannigan
After she played Willow on Buffy the Vampire Slayer and before her part on How I Met Your Mother, Alyson guest starred several times on the show as Logan’s sister.
11. Max Greenfield
Schmidt! He was Veronica’s boyfriend in Season 1, and came back as a guest star in Season 3.
12. Aaron Paul
Future Jesse Pinkman had a very small part on the show: He played a thug accused of murder in one episode.
13. Michael McMillian
Here, he’s a suspicious student involved in a bomb threat plot. But he will always be remembered as Steve Newlin from True Blood: “I’m a gay vampire American!”
14. Charisma Carpenter
Another Buffy alumna. On Veronica Mars, she played Kendall Casablancas, Dick and Beaver’s gold-digging stepmother.
15. Krysten Ritter
Before playing Jane on Breaking Bad, she was Gia, the mayor’s simple-minded daughter.
16. Courtney Taylor
His songs were used in several episodes of the show, and “We Used To Be Friends” was the song in the series’ opening credits. It only seemed natural that The Dandy Warhols’ lead singer would appear on the show. Of course, it’s a karaoke scene.
17. Britt Daniel
Neptune’s karaoke scene was pretty impressive: Spoon’s lead singer also stopped by to sing a cover of Elvis Costello’s “Veronica.”
18. Kevin Smith
The Chasing Amy director appeared at the beginning of Season 2 as a gas station manager.
19. Cress Williams
He’s mostly known for being Miranda Bailey’s ex-husband on Grey’s Anatomy. Here, he was Wallace’s estranged dad. And this wasn’t his last stint as a bad father, since he went on to play Vince Howard’s ex-convict dad on Friday Night Lights.
20. Michael Cera and Alia Shawkat
The young stars of Arrested Development both appeared in one episode of Season 2, as students of Hearst University. Alia Shawkat played a rape victim whose head was shaved, foreshadowing Season 3’s main investigation.
21. Christine Estabrook
She was Martha on Desperate Housewives, Marcy on American Horror Story’s first season, and she’s now playing Joan’s mom on Mad Men. On VM, she was a fortune teller.
22. Armie Hammer
The hot Winklevoss twin appeared at the beginning of Season 3; he played a football player who lost his playbook.
23. Rachelle Lefèvre
If you’re familiar with the Twilight trilogy or the shows Off the Map and Under the Dome (nobody’s perfect), then you probably know her. On Veronica Mars, she played a sorority girl.
24. Chris Lowell
Before playing Dell in Private Practice, Chris Lowell played Piz, a musician with a ridiculous name and Lego haircut who fell in love with Veronica in Season 3.
25. Joss Whedon
This doesn’t really come as a surprise, but the creator of Buffy was apparently a big fan of Veronica Mars. In Season 2, he made a cameo as a stuck-up employee of a rental car agency.
26. Ryan Devlin
SPOILER ALERT: He played Mercer, Season 3’s serial rapist. Then he went on to play Seth on Brothers & Sisters.
27. Matt Czuchry
Before he got the part of Cary on The Good Wife, he appeared in Season 3 as Logan’s fake brother. Logan wasn’t happy about it.
28. Laura San Giacomo
The Sex, Lies and Videotape and Pretty Woman actress played Harmony in Veronica Mars, a married woman who falls in love with Keith.
29. Jonathan Bennett
AKA Aaron from Mean Girls. He was a kid from Veronica’s high school, suspected to have joined a cult.
30. Ryan Eggold
The show 90210’s hottest teacher played Logan’s real brother, also a teacher. Also very hot.
Correction: An earlier version of this post misidentified Jonathan Bennett as Adam Kaufman.