Emergency Rules
2400 is a series of lo-fi sci-fi micro RPGs. Each is a self-contained game that fits on 3 pages and a cover¸ two sides of a letter-sized sheet of paper. They're all in the same setting¸ unless they aren't. And they're all are built with the same rules as the free 24XX SRD.
These are the Emergency Rules. 2400 is designed to be ultra light¸ super quick¸ and extremely open to interpretation. But what if you need more? These (very slightly) expanded rules give a little more context for players and GMs who might be more used to games with more detailed rule sets. They explain why there aren't any hit points¸ how combat could be (but isn't necessarily) run blow-by-blow¸ and why it sometimes makes sense to succeed on a 1. And they make expllicit some things that a lot of games assume you should know. (Like: "Come up with excuses to go adventuring and face danger together. If your character wants to escape to safety and retire¸ let them. Then make a character for this game.") Give us a shout if there's anything we ought to add.
What is lo-fi sci-fi? It's centuries in the future¸ and it's a decades-old modem that screams like a dying robot when it connects to the net. It's a space ship with an FTL drive¸ artificial gravity¸ and a flickering display you gotta tap a few times to see the jump coordinates. It's hacking something together with whatever cheap materials you have on hand¸ ignoring the rules until you need them¸ banging out something that might not sound finished¸ but definitely sounds fun.