Of course I mainly know him from Star Trek, but there were also several episodes of Heroes; a few eps of The Neighbors; an ep of Fresh off the Boat; as well as guest appearances as himself in various things. And he posts lots of cool memes on facebook. And he's done a bunch of voice work.
I know him from The Larry Sanders Show; and Max Headroom; and Muppets from Space; and There's Something About Mary; and the Hellboy movies; and Arrested Development; and How the Grinch Stole Christmas; and the very short-lived sitcom Bent; and an episode of Psych; and Paul; and Eurotrip; and some voice work.
I know him best from Doctor Who (and an episode of The Sarah Jane Adventures). There's also Fright Night; and Harry Potter and the Goblet of Fire; and Good Omens; and voice work in The Pirates! In an Adventure with Scientists!.
Thornton, Billy Bob
First thing I remember him from is Hearts Afire, though I may have seen him in stuff before that. I also know him from Bad Santa, and The Ice Harvest. And he voiced Jigo in Princess Mononoke.
Of course, there were the Back to the Future movies. Also, The Hat Squad, which I wish I remembered better than I do. And Little Spies. And Top Gun. And probably some other stuff...
I know him from Beautiful Dreamers; and The Larry Sanders Show; and Men in Black (and its sequel); and Marie Antoinette; and Zoom; and several episodes of 30 Rock; and he voiced Zeus in Hercules. And I've surely forgotten some things.
I know him from Studio 60 on the Sunset Strip; and Mr. Sunshine; and Weird Loners; and an episode of Supernatural; and an episode of Gortimer Gibbon's Life on Normal Street; and an ep of For the People; and maybe some things I've forgotten.
I know him from Carrie; and Grease; and Welcome Back, Kotter; and a couple of Look Who's Talking movies; and Pulp Fiction; and Hairspray; and he voiced the title character in Bolt.
Best known as Mini-Me in a couple of Austin Powers movies, though he's had better roles. There was a recurring part on Jack of All Trades, and a TV movie called Karroll's Christmas, and The Imaginarium of Doctor Parnassus.
I know him best from Firefly and its spin-off movie Serenity. But there's also A Knight's Tale; an episode of Arrested Development; a few eps of Dollhouse; V (the reimagined series); Suburgatory; and a small role in Abraham Lincoln: Vampire Hunter; and Powerless. And some voice work.
I know him from a couple of Lord of the Rings movies; and The Chronicles of Riddick; and the Star Trek reboot; and RED; and Dredd; and Almost Human; and Thor: Ragnarok; and possibly some things I've forgotten.
I know him from Keen Eddie; and Boston Legal; and Human Target; and Crisis. I may have seen some other stuff I don't really remember.
Van Der Beek, James
I know him from Dawson's Creek (though I've only seen the first season); and a cameo as Dawson in Scary Movie; and a fictionalized version of himself on Don't Trust the B---- in Apt. 23; and a few eps of How I Met Your Mother; and maybe some things I've forgotten.
I know him from Gilmore Girls, and Heroes, and American Dreams, and Cursed, and a recurring role on Gotham, and The Whispers.
No doubt I saw him in various things before this, but the first thing I really remember him from is State of Grace. And no doubt I've seen him in various things since then, but the main one I remember is American Dreams. And there were a couple eps of The 4400.
I know him from The Dead Zone; and Batman Returns; and Pulp Fiction; and Sleepy Hollow; and Man on Fire; and Wedding Crashers; and Hairspray; and Peter Pan Live!; and I feel like I should've seen him in other stuff. Um, he guest hosted Saturday Night Live a few times maybe. And there was the music video for Fatboy Slim's "Weapon of Choice." And an ad for Kia Optima.
Ward, Zack (no relation)
I know him from Titus; and Resident Evil: Apocalypse; and a couple eps of Dollhouse; and surely some things that I've forgotten.
I know him from Time Bandits; and Time After Time; and Tron; and Star Trek VI; and A Christmas Carol; and a minor role in Scream 2; and Titanic; and Wing Commander; and Teenage Mutant Ninja Turtles II; and an episode of Doctor Who; and Mary Poppins Returns; and some voice work. I've probably seen him in some other stuff... though I think I sometimes confuse him with Alan Rickman...
I know him from a relatively minor role in Batman Begins; and from The Last Samurai; and Memoirs of a Geisha; and Inception; and Cirque du Freak.
There's the Matrix trilogy; the Lord of the Rings trilogy; V for Vendetta; Captain America: The First Avenger; he voiced Megatron in the Transformers movies; and a couple of voices in Legend of the Guardians: The Owls of Ga'Hoole. And I've probably seen him in some other stuff.
I know him from Wings; and Studio 60 on the Sunset Strip; and the miniseries The Shining; and The D.A.; and Reefer Madness; and an episode of Monk; and Grow Up, Timmy Turner!; and a few eps of Falling Skies; and an episode of Sleepy Hollow (as Thomas Jefferson's hologram); and a couple eps of iZombie; and voice work in Marvel Rising; and probably some other things...
Weiss, Michael T.
Know him best from The Pretender. But there's also some voice work.
I know him from Batman; and Danger Theatre; and Monster Island; and an episode of Powerless; and probably numerous guest appearances as himself on various shows; and some voice work.
I know him from Adventures in Babysitting; and Bicentennial Man; and Little Manhattan; and Studio 60 on the Sunset Strip; and The Good Guys; and The Cabin in the Woods; an episode of Brooklyn Nine-Nine; and Get Out; and Saving Mr. Banks; and the short film Agent Carter.
I know him from Willy Wonka & the Chocolate Factory; and Young Frankenstein; and Blazing Saddles. And I think that's about it, but I should probably see more of his work.
Of course, first and foremost, he was The Fonz, on Happy Days. I also know him from Scream; and an episode of So Weird; and several episodes of Arrested Development; and probably some things I've forgotten. And he voiced Grandpa Bill in All I Want for Christmas Is You.
I know him from The Journey of Natty Gann; and Reaper; and a couple eps of Psych; an episode of Dollhouse; an episode of Castle; several eps of How I Met Your Mother; an episode of Deadbeat; Good Night, and Good Luck; a small role in X-Men: First Class; a recurring role on Fresh off the Boat; season two of Agent Carter; and Jeepers Creepers II; and Gilmore Girls: A Year in the Life; and the Funny or Die short The Girl with the Tramp Stamp Tattoo; and I've probably seen him in some other stuff...
He had a very small role in Back to the Future Part II. And I probably saw Radio Flyer at some point, but I don't remember anything about it. Same with The Ice Storm. Of course I know him best from the Lord of the Rings movies. There was also Eternal Sunshine of the Spotless Mind, and Everything Is Illuminated, and I saw maybe the first couple episodes of Wilfred. He also did voice work in 9, and Tome of the Unknown/Over the Garden Wall. And I've probably seen him in other things that I've forgotten.
I know him from Special Unit 2; and a recurring role on Seinfeld; and Watchmen (+ Under the Hood); and Mirror Mirror; and I'm sure I've seen him guest on various shows and in some commercials and stuff...
I know him from The Equalizer; and A Christmas Carol; and Over My Dead Body; and an episode of Crusade.
Mainly know him from ALF. There's also A Midsummer Night's Dream; and I'm certain I've seen him in other stuff I don't really recall.
I know him from what little I watched of ER; and Swing Kids; and Donnie Darko; and White Oleander; and The Librarian TV movies; and Falling Skies; and The Red Line.
I know him from Mary Poppins; and Babes in Toyland; and The Gnome-Mobile; and a couple eps of The Twilight Zone; and he voiced the Mad Hatter in Alice in Wonderland. And he's done other stuff I should see someday.