Our 3.5/AE/DM Fiat campaign --which is either called "The Chronicle of Burne and Some Others of Lesser Importance" or "More Tales of CITY"-- will continue until I just can't run it anymore. Everyone's currently 13th level. An endgame scenario is just starting to develop, but who knows when or if we'll get there (I hope we do, said looks like it'll involve storming Heaven in a knock-off TARDIS, a mystical Real Doll, time travel, the Omega Point, and one PC potentially fighting his future self who's the BBEG).
In addition to that, my friend who plays Burne is planning a 4e campaign in a new homebrew this fall, and sometime after that, I'll run a 4e game in my old homebrew CITY.