Welcome, Ewoklord! I'm running three games, one of which is new and another of which has had a new beginning of sorts. None of them are 1920s, unfortunately. My first Doctor Who/Call of Cthulhu game, The Terror Out of Time, was set in 1930 London and recently finished. However, it is the first scenario in a planned campaign. I started the second game, The Ninth Planet, a little over a month ago. It is set in 2112, but you won't need to worry about character creation. Other than surviving characters from the first game, all characters are pregenerated in that one. All of them were claimed, but one player was a no-show and another abandoned a character, so there's room for two more. I have plans for further adventures in this campaign that will sample other eras.
Zombie Apocalypse is modern day non-Mythos survival horror and has been running for over five years now, but I'm in the early stages of Chapter 7, which actually marks the beginning of the second day of game time (a
lot has been going on during the first day!
). There are several new pregenerated characters I've added for Chapter 7, and you can also create one or two of your own, with which I can help you. It only started in the last few weeks, so there's little catching up if you play only new characters.
Space Oddity has been running for about two and a half years. It's set in 1969 Philadelphia and is inspired by Life on Mars/Ashes to Ashes. However, it moves slowly and you could join in without too much trouble, either taking over an abandoned character or creating a new one. Only about 24 hours of game time have passed since that one started.
Raiko is planning to resume Masks of Nyarlathotep shortly, which is set in 1925. The game is currently in London. He said he doesn't plan to recruit any new players, but you could ask to join. He also might later resume Beyond the Mountains of Madness, set in 1933. That game has already reached Antarctica.
Kabukiman also might resume Escape from Innsmouth, set in 1927, once he finishes his current game. If he does, he'll be looking for new players, as everyone but me seems to have vanished.