Which system(s) are you itching to play but haven't yet?
Whether it be due to scheduling, lack of interested players, or some other reason, what's an RPG system you're just hoping to get to the table one of these days but haven't been able to yet?
Some of these I have/am running as a GM, so it's mostly "in what game do I want to be a player in"?
Shadowrun, Traveller, Symbaroum, Rogue Trader, Warhammer Fantasy RPG, Cyberpunk RED and/or 2020, Star Trek Adventures