The main idea I'm theoretically working on (once I finish some things I need to get done before the holidays) is something involving making your own Tarot deck. The draw-on-the-cards thing from Other Worlds is an inspiration there, and the current plan is that different players will have some responsibility for each suit of the minor arcana (inspired by Quarterdeck), and you need to create the Major Arcana by doing random TVTropes pages (inspired by All-Devouring Monomythic). I was originally thinking it would be a parallel worlds thing and you'd have a story based around politics and journalism but that felt pretty flat to me, so I'm currently thinking of going in a more supeheroes kind of direction. It will likely have a card-drafting element, like in An Unfinished Draft. I haven't really written anything down yet, though, and I'm kind of vacillating on whether I think I can make it work.
I have a backup idea, which takes the "simple strategic wargame" thing from A Theoretical Tactics Game and the "your hitpoints are you party" thing from Colander: have a simple light wargame where one player is the Dark Lord and the rest of the players are the Last Alliance, and you play out the battle where the alliance fails to stop the Dark Lord from seizing power, but the process helps do the world- and character-building to set up an Epic Fantasy scenario (e.g. the survivors of the units from the various factions are PCs, or NPCs who learned vital information during the confrontation, etc.). I'm not sure if that's just the setup phase for a game I would design, or if it's kind of like a scenario generation bolt-on for a more conventional RPG.
Also, I think that the situation sketched out in The Body Comes Alive would mesh well with the mechanical structure of my game Rusty from Disuse, but I don't think I'm the right person to write a game like that. I'd be open to collaboration if somebody else was interested, though.