Surprised it's not mentioned here, but Bzflag.
Super fun tank shooter game that doesn't take much to run, and reminds me of a cross between the very old bolo game and Mario kart's battle mode.
From video gaming to card games and stuff in between, if it's gaming you can probably discuss it here!
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Surprised it's not mentioned here, but Bzflag.
Super fun tank shooter game that doesn't take much to run, and reminds me of a cross between the very old bolo game and Mario kart's battle mode.
Tremulous - The game was so fun back then (like 10 years ago ?) I guess it's a dead game now.
osu!lazer
For me it's CDDA, a quite realistic and deep apocalyptic survival game with very frequent updates(on the experimental branch)
classicube is pretty cool, open source Minecraft classic-like game (so, no crafting or survival aspects, limited world sizes)
I'm surprised to not see Flare RPG mentioned. It's nothing groundbreaking on its own, but it's actually got two nicely fleshed out campaigns, and tooling for people to make new ones. It's a nice, fun, FOSS single-player RPG, and it's great if you want that old fashioned Diablo feel.
Another vote for Endless Sky here as well, it's just excellent, and surprisingly expansive.
Aside from the other choices already mentioned (especially Doom stuff, FreeDoom ftw) any of the free games derived from the S.T.A.L.K.E.R. games and early builds, mostly Anomaly and Lost Alpha. There are also a few stabilized versions of the Build 1935 alpha out there which are worth playing and probably a bit more approachable for most people.
Technically not the whole game, but Smash Remix is an open source rom hack of the original Super Smash Bros. for the Nintendo 64. It's been a blast from the past and I'm enjoying the hell out of it.
I also love the fact that a lot of N64 emulators are open source too, like Mupen64 or simple64
I made one! It's a solitaire-like but with some new mechanics, and fairly polished and balanced at this point. You can find it on itch and on the play store. Here's the source.
One of my absolute favorite games as a kid was Glest. Turns out it's open source and is now available as MegaGlest!
It takes a lot of inspiration from Warcraft but it has its charm and many of the races are quite unique in how you play them!
Pokemon Auto Chess. Literally what the name implies, a Pokemon auto battler fan game. Honestly it's really well-polished for something only a couple of people are working on (aside from commissioned sprite artists) and has an active community to go with it.
Arguable if you can call it a game or not, but there is Overte. It is an open-source social VR platform. (without crypto so please no pitchforks)
As one of its developers I might be biased, but I wouldn't be one of the developers if I didn't honestly believe in the project.