Lines of Experience
So, the recent Marvel Superheroes RPG, the one with the stones system, was really interesting, but as I understand it, died because it was published by a comic book publisher. Good numbers for an RPG are bad numbers for a comic, or so I am led to understand.
Anyway, even if you never get to play it, it's worth nowing about its advancement mechanics, "Lines of Experience". Characters were medium-grained in detail, and when you gt advancement, it was given as "lines of experience". Now, mechanically, each waas basically a point which you assigned to the thing you wanted to improve. if your kung Fu was a 7, you assigned lines to it, and after you accumulated 7 of them, it became an 8. Easy peasy.
But where it got interesting was that for each line you actually wrote a brief description of what you had done with that skill durng the adventure, like "Fought the Sinister Frogmen of Yslar in their underwater lair" and if on a subsequent adventure you are in a similar situation (fightign underwater, say) you could use that line of experience to temporarily boost your skill from a 7 to an 8.
I love this idea, and Fred Hicks ended up riffing on it nicely in Don't Rest Your Head, but I think there's a lot more to be mined out of it.
I sometimes need to actively remind myself that the Amber Diceless RPG is a small, niche game. This is hard because it's SO big and SO influential on me that I sometimes forget that not everyone else has is burned into their heart. And that means not everyone has been as exposed to the ADRPGs player contributions.
So Amber had a simple point-buy system, with 100 points to spend, but plyers could get extra points, usually in 10 point blocks, for maing contributions ot the game. Contributions included drawing pictures of the characters, keeping a character journal, writing stories about your character and so on. Over time different groups expanded what qualified as a contribution to include things like hosting or buying food.
Now, bear in mind, this was the time before Livejournal and fanfic communities, so the fact that the game provided a legitimate outlet for other types of creativity was a huge win in terms of creating player investment. What's more, by granting players the leeway to author a lot of "offscreen" materials, it proved one of the few ways to really get player investment in setting that's on par with killing Elminster.
Now, not every game necessarily calls for fiction or the like, but every game calls for _something_. If there's some sort of behavior or investment you want to encourage or acknowledge, then consider formalizing in-game rewards for player contributions. It's not fair in the traditional sense, but that tends to make it more motivating: you recognize your contributing members and provide others the opportunity (and clear direction on how) to do the same.
1 - This gets its name from a tale told on the Sons of Kryos podcast, of a D&D game where the opening even is the murder of Elminster, the iconic NPC of the Forgotten Realms. This sort of actionis a clear dramatic statement that the game is not going to be dictated by the official canon of the setting, and that the table owns the game.