Since JP, Cohh, and Zeke will be doing the Game of the Year stream soon I wanted to see what everyone lists as their “5 games everyone should play at least once”.
Here are my five (in no particular order):
• Pokemon
• Stardew Valley
• World of Warcraft
• Bioshock series
• Life is Strange
For me, in no particular order.
Witcher 3
Warcraft III
Metal Gear Solid 4: Guns of the Patriots
Half Life 2
The Legend of Zelda: The Ocarina of Time.
Banjo Tooie.
For me the words “at least once” seem relevant. While games like Witcher 3 are amazing, they take a while to go trough.
I feel like these games are something that can be appreciated or seen the core of it in a smaller chunk:
Guitar Hero / Rock Band
Wii Sports bowling and tennis (boxing is optional and sweaty)
3D Zelda game
Duke Nukem 3D
Katawa Shoujo
By “Play at least once” I thought Twistedgerm meant specifically play through its entirety? If thats not what he meant, then at least my list I was going with the understanding, play through to completion.
I think we can take it as we want. I just wanted to say what seemed relevant for me. 
Best feelings that i remember from completing a game are Witcher 3 and Rimworld. Having to do any kind of list for that seems too daunting as there are more than 5 i would want to mention. 
Gah so hard to do these haha. So many good ones! Obviously there’s more but I’ll try 5.
Here are some of mine in no particular order:
I was mostly referring to games you would tell someone new to gaming they “have to” play through.
Kind of like people say you have to try a certain food before you die type of thing.
Apocalypse World
Dungeons and Dragons (Moldvay)
The Burning Wheel
Fiasco
Fall of Magic
• SUPER MARIO BROS - The first game on the first system I ever owned and quite important to gaming’s evolution
• DARK SOULS - an evolution of old games that didn’t hold your hand, tough but fair
• THE WITCHER SERIES - bit of a cheat but shows the evolution of a game series and studio
• DIABLO II - as much as I love the original, the sequel just eclipses it, the customization, the story telling, and the loot drops
• HALO: COMBAT EVOLVED - Just a great shooter, played it at a friends house and bought an X-Box just to keep playing
hm… if i looked at the question in that light then i’d pick ones that really exemplify specific genres while still being approachable (aka: Sim City instead of Dwarf fortress for micro management games) and i’d pick things like, Shadow of the Colossus, Bioshock, Journey, Minecraft, etc.
However, if i wanted to just pick my all All-Time-Favorite-It-Would-Be-Awesome-If-You-Loved-These-Games-Too!!! list, it would be:
Dragon Age Origins (Loved this one!)
Tales from the Borderlands (Seriously, such good characters and story! Also amazing intro music scenes)
Dwarf Fortress (because FUN!)
Fallout: New Vegas (For some reason i got more immersed in that one then in Fallout 3)
Deus Ex: Human Revolution (I don’t know, i just love this game)
Kingdom Hearts get’s an honorable mention as it was really the game that got me into video gaming <3
I took this to mean all types of gaming, pen & paper, video games and even cards.
In no particular order:
Fable 1 - One of my favourite games, and one of the only games I can constantly go back to and never be bored.
Starcraft: Brood War - The campaign to be exact! It’s tacky, the graphics are out dated, and fuck the AI but god dammit this game is so fun. You run around with your 12 badass zealots and just have so much fun.
Dungeons & Dragons - Any system, but i’d say 5th for the sake of easy to get into. I feel like any gamer should experience pen & paper gaming, even over Roll 20. It makes you look at other games in such a different light.
Magic the Gathering - This is a harder one to actually play at least once, simply because of the investment it takes to play once, both money wise and time wise. However if you know someone who has at least two decks, knows the rules and has the patience to teach you I feel that MtG can be such a rewarding game played casually. Maybe I’m biased, my mother taught me!
Empire Earth - Such a fun, wacky, weird, lovable strategy game. My first strategy game and what made me fall in love with the genre, the mixture of going through the ages from pre-historic to space age has something for all different strategy players.
Civilization 5 - Or 6 since it has most of 5’s features without expansions, but you can usually get 5 at a good price.
Saints Row 3 - And/or 4, their both fun.
South Park: The Stick of Truth - Best played if your a South Park fan.
FTL: Faster Than Light and One Finger Death Punch - Just plain fun!
Here are mine in no particular order:
Brothers: A Tale of Two Sons - I can’t explain why on this one, if you play it you’ll get it.
Portal - Shows how computer gaming can be used to bend your perception to solve problems, while also conveying a reasonably compelling story.
Dungeons and Dragons - Any PnP RP would work, but DnD has more cultural context to make it meaningful. This is to understand how to create play experiences without relying entirely on an authoritative rulebook
Settlers of Catan - A very good example of a competitive building board game, in comparison to say monopoly.
Half-Life 2 - For the breadth of story elements that get conveyed through the FPS medium. There are a variety of different styles of experience through the course of the game.
EDIT: Besides PnPRPG’s obviously.
D&D, as many different editions as you can, just to get to experience all the ways to dungeon crawl.
Planescape: Torment
Taking one of the cliche concepts, the amnesiac protagonist, and doing everything with it.
Rarely has a game offered as many small moments that stick with you, because they all define who your Nameless One is and up until the end it still throws suprises at you.
Even if you expect some of the things, when they happen, they hit you hard. “Think of the trees” “Is that correct?” “Have I been here before?”
Battlestar Galactica Board Game
The current pinnacle of the cooperative traitor genre. While the base game has a few flaws, like an a bit uneven pace with uneventful turns and then sudden moments of impossible crisis, the expansions make it an impressively adaptable game, each offering different options and win conditions, marvelously capturing the feel of each season of the show, while being completely playable and enjoyable without any knowledge of it.
I’ve played that game over a hundred times by now and only a very few people it didn’t click with and many love it who never watched a mintue of the show.
Super Mario
Be it NES, or GB, or a new version. You should have jump’n ran the plumber.
CIV
17:00: Hmm, don’t like this 4X stuff…let’s see… how does this work? Man, I suck at this. FU (insert neighboring warmongering nation). One more turn. Damm, lost. Oh well, got time for another turn or two, early game’s not much to do… HAHA, take that barbarians… That’s my gold, fuck off Japan! Pheww, got tanks now, sweet.
Hmm, should sleep I’ve to get u…5:55!!!
Honorably left out: Dark Souls. It does so much for people it clicks with, so I want to include it, but for whom it does not work, it’s like you handed them a Buddhist text in sanskrit and a dictionary claiming: “It’s worth the effort”.
They’re either confused by the suggestion of so much effort for seemingly nothing or try to put in the work and get seriously annoyed why their time was wasted on this horse shit.
Dragon Age: Origins
Mass effect series (Minus the ending)
Witcher series (Or at least 2 and 3)
The Wolf Among Us, or Tales of the Borderlands from Telltale. Great series.
Baldur’s gate 2
I’ll stick to video games since I know them better than tabletops. My list is intentionally well rounded. Not necessarily my top 5 favorite games, just the top 5 that I think would have the biggest impact on a non-gamer to learn what gaming is about.
God damn, I needed a list of ten!
It’s difficult to make a list of only 5 games, but I think these are the ones I would recommend. I tried to not include too much personal bias, like nostalgia etc that might affect my opinion of a game.
My little list:
I’ll just name the games I thought were fun and that I feel nostalgic about 
Honorable mentions: