Crossovers: Doppelganger fic
Slashfic concept my husband came up with: Doppelganger fic, or crossover stories featuring two characters played by the same actor in movies or TV shows.
This is a repost of something from a while back at LJ; I'm not sure if I imported it to IJ or not, but it belongs here anyway. (Even if it will drive me crazy with the tags.)
Hugh Laurie: House/Wooster (House is forced to take a vacation, and books a tour on a cruise ship--which goes into the Bermuda Triangle, gets caught in a storm, and big crashes start happening. The modern ship is mixed up with one from the late 20's/early 30's, on which Wooster is partying. Some friend of Wooster's is ill, and House has to try to treat him or her, around Wooster's "help.")
William Shatner: James T. Kirk/T.J. Hooker (On one of those visit-the-20th-Century missions, Cap'n Kirk meets a police officer...)
Alan Rickman: Severus Snape/Hans Gruber (Pre-Die Hard; Hans is pulling off a bank robbery in Scotland and unknowingly grabs a Death Eater as a hostage.)
Johnny Depp: Jack Corso/Wade "Crybaby" Walker (Crybaby visits a new bookstore on the edge of town.) Alternate: People who know 21 Jump Street might find interesting ways to cross Officer Tom Hanson with either of these.)
Kyle McLaughlin: Agent Cooper/Paul Atreides (Paul does some deep trance visitations to his past, and finds an FBI agent among his ancestors)
Eddie Murphy: Axel Foley/Mr. Robinson (A rule-bending cop visiting New York comes across a clever burglar.)
Kurt Russel: Snake Plissken/Jack Burton (Snake hitches a ride with a truck driver. Probably pre-Escape movies.)
Bruce Willis: David Addison/John McClane (Detective meets cop. I'm not giving a plotbunny here; there are too many.)
Ian McKellen: Magneto/Gandalf (Magneto plays with a dimension-warping device that brings him face-to-face with one of the guardians of Middle Earth.)
Patrick Stewart: Professor X/Captain Picard (Sequel: Professor X gets the device away from Magneto, and does some experimenting of his own.)
Hugh Jackman: Wolverine/Van Helsing (No plotbunny; I haven't seen Van Helsing. But I'm sure you folks can think of something. And I'm sure that device is still floating around.)
Keanu Reeves: Constantine/Ted (Ted goes wandering around the multiverse in the phone booth and almost gets caught by demons, but is rescued just in time.)
Harrison Ford: Han Solo/Indiana Jones (An accident with the warp drive dumps the Millenium Falcon in 1940's America.)
Sean Connery: James Bond/Professor Henry Jones (15 years or so after the end of the war, Indiana's father is doing research in a British museum when shots ring out. A dashing young spy hauls him out of the firefight.)
Christopher Eccleston: Dr. Who/Prisoner (Not yet possible... Eccleston has been cast for a remake of the Prisoner, but it hasn't been made yet. This is the pairing that inspired the rest of this twisted idea. The TARDIS lands in the village, and Number Six tries to arrange an escape with the Doctor.)