As @Naatkinson indicated, the Cypher system is the core mechanic to Numenera. Typically, you would have thought Monte Cook Games would have released the mechanics (eg Cypher) then produced setting materials (eg Numenera), but instead, they did the exact opposite. Numenera was first released and was both the setting and mechanic, then The Strange came out as an alternative setting using the same mechanics, then they released the Cypher System Rulebook, which embodied the base mechanics as well as providing instructions on adapting the mechanics to fit pretty much any settings. It's a very flexible mechanic system.
For those who aren't familiar with it, the Cypher mechanics can be boiled down to the GM deciding how difficult a task is (on a scale of 1-10) and the players can trigger things (ranging from skills to assets to putting more effort into it) to reduce the difficulty. Then the player rolls a d20 and if the result is equal to or greater than the difficulty times 3 (eg a Difficulty 4 requires rolling a 12 or higher), the player succeeded. And that's about it. Getting deeper into the mechanics targets the various ways the players can reduce the difficulty, but at the end of the day, it's not very complicated. It's really easy on a GM because they're only responsible for crafting the story/environment and assigning difficulties. Everything else is in the hands of the players (aka the GM never rolls the dice).
The other thing that defines the Cypher system (and how it gets its name) is how it leverages one-use items (dubbed 'cyphers') to give the players greater-than-average abilities. For example, a Tier 1 player isn't going to be able to teleport or levitate, but if they had a cypher, they could do so...once. It puts a lot of power in the players hands for thinking outside the box in an encounter and gives them 'spotlight moments' that are (IMO) necessary for a fun game.
Regarding the Numenera setting, it's what we might expect the Earth to be like a billion years into the future. There have been eight civilizations that have ascended and fallen, each leaving behind remnants of their brilliance. In this Ninth World, magic (called numenera) is pervasive, and while many can wield it or have been changed by it, few truly understand it.
I'll give it some more serious thought tonight and tomorrow, but I'm leaning toward starting up a game since there's such interest. And if I use the Cypher: Numenera OP materials (which is highly likely), it'd be easy enough for me to hand the reigns off to another GM (eg @Qralloq) if it becomes too much for me to run. The last thing I'd want to do is start something up and then have to pull the plug on it after only a couple of weeks due to an over-commitment on my part.
