They’ve appeared in countless shows, they’ve worked with some of the biggest names in Hollywood, and their resumes boast endless award-winning films and series–and you have no idea who they are. Well, you do, kind of; its just that their on-screen appearances are welcomed with “OH! It’s THAT guy!” or “Shit, what’s she in again?” Repeated CSI appearances, guest spots on Law and Order , the eternal best friend of the main character– they’re everywhere, all the time, and you still don’t know their names. But instead of accessing your nearest laptop in hopes of endlessly scouring IMDB for answers, may I present you with a list of actors you didn’t know you knew – until now.

Jane Lynch

Millions of people now know her as Sue Sylvester on Glee. If you’re not one of them, well, let me introduce you to a woman who has over 130 IMDB credits, thus officially deeming her an “acting powerhouse”. (I’ll admit–I only recognized her as Reid’s mother on Criminal Minds.)

After playing Richard Kimble’s ally in The Fugitive, Jane went on to basically pwn 90s television by appearing on everything from Party of 5 to Dharma and Greg to 3rd Rock from the Sun to Dawson’s Creek. As the 2000s progressed, she continued to perfect her acting strategy with an intensity that mimicked the determination of a Brangelina adoption plan, appearing on The L Word, Family Guy and Two and a Half Men. If you think you’ve seen her in everything, you probably have. She’s probably even standing outside of your house as we speak.

Harold Ramis

I know what just happened: you saw his picture and immediately exclaimed “THE DAD FROM KNOCKED UP!” And you would be correct. But what you don’t know is that prior to becoming a staple of the Apatow family, Harold was an incredibly successful writer and comedian who counts Animal House, Ghost Busters and Groundhog Day as his written achievements. Basically, the man is a legend (he wrote GHOST BUSTERS for Christ’s sake!), and I’m ashamed that I didn’t instantly give him the credit he deserved.

In addition to appearing in his written work and films like High Fidelity, Harold was also an original Second City alumni, pioneering SCTV alongside the legendary John Candy, Eugene Levy and Dave Thomas. I’m actually pretty sure that without Harold, pop culture would not exist. If you can, imagine a world without Ghost Busters…imagine comedy without Caddyshack…imagine toga parties without Animal House…yeah, I know. So the next time you hear someone announce “the dad from Knocked Up!” you must immediately batter them to death with a club of pure guilt for their lack of knowledge regarding one of comedy’s greatest gifts.

Alan Tudyk

If you’re anything like me (teens of the early 2000s, I’m looking at you), when you saw Alan in Knocked Up as the carefully-worded E! executive (“I might say ‘tighten’?”), you quickly associated him with the comic relief of 2001’s A Knight’s Tale starring the beloved Heath Ledger. This man might be the number one recipient of the “Oh THAT guy!” shriek.

For as your realization sets in, you remember (or you should): Patch Adams, Firefly, 28 Days, Wonder Boys, Ice Age, I Robot, Arrested Development and 3:10 to Yuma… Anyone? Yeah, you’ve seen him before. These are merely samples of his extensive filmography. Since 1997, Alan’s worked alongside everyone from Robin Williams to Michael Douglas, and though his current project Glenn Martin DDS (?) may not launch him into stardom, at least you can finally watch Knocked Up without the constant “what’s he in again?” nagging in the background.

Paul Schneider

Unless you’re pretty well-versed in quirky independent film, you’ll only know Paul as Mark Brendanawicz (Amy Poehler’s love interest) on NBC’s Parks and Recreation. And even then, you still might not be able to place him since the show isn’t exactly groundbreaking. But what may surprise you is that prior to his turn as the clueless blue-collared citizen of Pawnee, Paul appeared in various films that boasted actual critical acclaim. Not just prime-time dramas for this bloke.

After appearing in The Family Stone and Elizabethtown, Paul played Ryan Gosling’s deeply conflicted brother in the beloved and award-nominated Lars and the Real Girl, then went on to appear in Sam Mendes’ lovable Away We Go. The man also acted alongside Brad Pitt and Casey Affleck in The Assassination of Jesse James by the Coward Robert Ford and co-starred with indie darling Zooey Deschanel three times since writing the 2003 film, All the Real Girls. Not bad for a guy who’s only been IMDB registered (let’s be honest, that’s the true mark of success) since 1997.

Judy Greer

Behold: Judy Greer. The universal “best friend”. The epitome of “THAT girl!” shout-outs. As far as you can tell, she has appeared in nearly every romantic comedy since the early 2000s. In reality, though she’s played gal-pal to Jennifer Garner (13 Going on 30), Jennifer Aniston (Love Happens) and Katherine Heigl (27 Dresses). Judy’s made over 60 film and television appearances since the late 90s, and has truly perfected the art of quietly stealing all the funny parts from the actual headlining star. Nice going, Judy.

Remember Kitty from Arrested Development? (Sure you do.) Brandy from Love Monkey? (No, me neither.) Ingrid from It’s Always Sunny in Philadelphia? (Obviously.) Regardless, from ER to House to Californication, Judy’s been there – and now you know it. So the next time your friends announce “It’s that chick who’s always the friend!” you can dazzle them with your knowledge.

Mark Moses

Duck Philips, anyone? Fellow Mad Men aficionados, you know exactly who this is. But what you may not know is that prior to playing the smooth-talking secret-drinking Madison Avenue ad man, he played Mary Alice’s troubled husband on Desperate Housewives (I know, I was shocked too when watching the re-runs one night.) Mark’s career has literally spanned decades, and in addition to the mandatory ER and CSI appearance, he’s worked alongside William Shatner (Boston Legal), Morgan Freeman (Deep Impact) and George Carlin (The George Carlin Show).

Now, unlike some others on the list, Mark has accepted more than his fair share of cringe-worthy scripts (Big Mama’s House 2, 7th Heaven, Monster in Law). Here’s a tip: read the scripts, my friend. However, with credits that include Perry Mason, Family Ties and Platoon, and over 80 movie credits, Mark might actually be “that guy that’s in everything”.

Catherine Keener

Like Patricia and David before her, Catherine is another example of a well-renowned actress who isn’t stopped in the street or headlining the box office. Though she’s recently been brought to the forefront after co-starring in Where the Wild Things Are, you’ll probably also recognize her as the lovable, understanding Trish to Steve Carrell’s awkward Andy in The 40 Year Old Virgin.

However, (to name a few), Catherine has also been seen starring alongside Philip Seymour Hoffman in the Oscar-winning Capote, Robert Downey Jr. in The Soloist and Emile Hirsch in the Sean Penn directed Into the Wild. Basically, she’s the modern day Mary Steenburgen. In fact, you might even say that Catherine ’s the fame-avoiding opposite of Mickey Rourke (unlike her, the man loves headlines and plunging necklines).

Julie Walters

If you love all UK-based media, you’ll recognize Julie Walters as a staple of British film and television, appearing in period pieces, Law and Order equivalents and even the quirky and offbeat. But what may shock you most (at least it shocked me) is that this auburn chameleon is actually both Mrs. Weasley from Harry Potter AND one of Meryl Streep’s BFFs in the musical Mamma Mia. (I KNOW!)

And once you make that connection, you’ll recognize her in nearly everything offered from across the pond. Did anyone see Driving Lessons starring Rupert Grint (aka Ron Weasley)? No? Well, she’s in that. Becoming Jane? (Ladies, you know you saw it for James McAvoy alone.) She’s in THAT. Calendar Girls? Yeah, you get my drift. (And really? You saw Calendar Girls?) At least now you can stop wondering why you feel uncomfortable about Rosie’s behaviour in Mamma Mia – we all know Mrs. Weasley would NEVER carry on like that.

Patricia Clarkson

Alright, there’s actually a significant chance you know exactly who she is, and if you don’t, shame on you. But just in case, may I introduce you to the wonder that is Patricia Clarkson. Though she’s currently starring in the independent romance, Cairo Time, Patricia’s often the supporting role to people like Robert Downey Jr., Ryan Gosling, Chris Cooper or Scarlett Johansson. Critically acclaimed films are her scene, often playing subdued-yet-emotionally-complex wives (Married Life, Vicky Christina Barcelona, Good Night and Good Luck), doctors (Lars and the Real Girl) and family members (Six Feet Under).

Of course, you may recognize her best as Justin Timberlake’s Andy Samberg-seducing mom in this year’s “Mother Lover”, or as Carol Parrish in 1995’s Jumanji (yeah, I know, that’s probably just me). Regardless, Patricia’s both a fox AND a legitimate film star who you’ll now probably recognize in nearly anything worth viewing. And when I say “worth viewing”, that clearly includes “Mother Lover”.

David Straithairn

I remember this guy best as uber-Jew Ira Lowenstein in 1992’s A League of Their Own, but you’ll probably recognize him best as Noah Vosen in The Bourne Ultimatum or as the historic Edward Murrow in Good Night and Good Luck.

An Academy-nominated actor (and STILL no one knows how to pronounce his damn name), David’s filmography begins in the early 1980s and shows no signs of slowing down, with six films scheduled for release in the next year. However, like his counterparts on this “esteemed” list, David’s successfully maintained a low profile, seemingly refusing to climb aboard the shameless self-promotion train conducted by most of his colleagues. I know he’s probably above my – or anyone else’s – top ten list, but frankly, I’m just relieved to finally draw a Kevin Bacon connection between Geena Davis and Matt Damon.