Lightweight RPG for 2-4 player

Hi,

I'm asking the great Gamer's Plane hivemind for advice :D

I have a F2F-TTRPG group. While my players are all great in general they are a bit unreliable. Just today I had to call off our session because two players had no time and one drank too much yesterday.

So I'm looking for a TTRPG system which I can use for the days where not enough players show up. It should match the following criteria:

-Rather lightweight on the rules system so that I can quickly explain it to whoever comes to the sessions
-Somewhat scalable so that I can play it with 2-4 player whose attendance will vary
-Light on preparation. I want to be able to set up the game in a few hours time
-Preferably free or low cost
-I personally really like science fiction settings so maybe the system has a sci-fy setting or is adaptable to one. But it's not a must-have.

I've heard that the Traveller RPG is quite nice but I don't know if it fits these criteria.

Any help will be greatly appreciated.

I'm a big fan of Lasers & Feelings and its myriad hacks that allow virtually any genre and flavor. It lends itself toward silly fun, but if you and your players like RP, you can go deeper. And it's insanely easy to learn, teach, and play.

L&F is fun but very shallow mechanically so your players might get bored with it quickly if they like some mechanical depth. If they just want to roleplay and don't care about tactics and mechanics, it's a solid choice, though.

Maybe FATE or Savage Worlds might be suitable for your needs.

That's true. The mechanics of L&F are so light as to be nearly non-existent.

The Wushu RPG system hits all of those checkboxes. Some people find it a little too freeform, but it is really perfect for a last minute substitute. The rules can be explained in about 3 minutes, it scales very easily to any number of players, is available for free on the creator’s website and as a PDF on drivthrurpg, and while there is no default setting the PDF does suggest a number of different settings including some sci-fi ones. Wushu isn’t for everyone but it is my personal favorite game and I’m always going to recommend it to people.

For a more traditional RPG you might want to check out the old D6 system or its fan update Mini Six which details the entire system in around 30 pages. Both are available for free and D6 had specific books published for fantasy, modern, and sci-fi worlds.

http://danielbayn.com/wushu/

Hmm, I know many simple and free/cheap RPG, but none of them are sci-fi. I do know some free sci-fi games, but I have no idea if they are simple as I've never tried them.

You can always check out Icar and Eclipse Phase, both sci-fi and both free if they are what you need.

As for other genres/games...

D6 Pool: free and generic, but mostly geared towards modern-era play.
Warrior, Rogue, & Mage: free and very simple fantasy.
Dinky Dungeons: Free, very simple fantasy which doesn't take itself very seriously... Lots of jokes.
Dominion Rules: Free and simple, good for historical medieval or low fantasy games.
Devil's Crossroad: Free and simple western.
Shotguns n' Saddles: Cheap and simple western.
The Age of Shadow: Free/cheap simple fantasy.
Swords & Six-Siders: Free/cheap simple fantasy. Basically what if OD&D/AD&D used only a d6... Also has a sense of humor very similar to Dinky Dungeons above...
Atomic Highway: Free and simple post-apocalyptic.
Five Torches Deep: A cheap and simplified version of D&D 5 with a more old-school feel.
Vagabonds of Dyfed: OSR meets PbtA. Cheap and simple.
Uncharted Worlds: A cheap PbtA system to play space opera-type games (so sci-fi).
Dungeonslayers 4th edition: Free and simple fantasy which I feel is a notch above all the others. The talent system gives some interesting depth to character creation and build.

Thanks a lot for all the great suggestions! I really appreciate that.
I'll have a look at all the systems and then decide what best fits the group

My favorite for absolute ease of play is Simply6, its a minimalist d6 pool game that can be used for pretty much any genre. The rules for magic might need a little tweaking depending on taste. (For settings where magic is more prevalent, I change them so that magic users can cast as many spells per day as their Magic skill and they don't lose skill dice.) I'm not sure why, but this one of the few minimalist game systems I've played (and I've tried ALOT of them) where the resolution mechanics feel just right - where the outcomes are not too arbitrary and dependent on luck, and not too pre-determined.

Ah yes, that reminds me of Mini Six as well. Both games are probably very similar...